It was defined as a potentially pivotal portion of the season. The Red Sox were staring down the barrel of one of their most challenging stretches of 2010, facing a run of five straight teams that had emerged as early postseason contenders.

The 13-game stretch -- featuring road games against the Tigers (3 games) and Yankees (2), a two-game homestand against the Twins and then a return to the road against the teams with the best record in the NL (Phillies, 3 games) and AL (Rays, 3) -- seemed unrelenting. A falter could have jeopardized the Sox’ ability to contend.

The run did not start well. After the Sox won their first game in Detroit, they lost the next two contests there, as well as the opener of the two-game set in the Bronx. But since that time, the team has reeled off wins in five of its last six, including an 8-3 triumph over the Phillies and ace Roy Halladay on Sunday (recap).

The Sox are now 6-4 in this grueling stretch. They have held leads in the seventh inning or later in eight of the 10 games they’ve played thus far. In short, they have played some of their best baseball of the season against the best competition in the majors.

“We played really well. Even in [a two-game split in] New York, we played decent,” pitcher Tim Wakefield told reporters after improving his lifetime record in games against Halladay to 4-1. “We played really well against Minnesota and things are starting to click for us offensively, defensively and pitching.”

For a team that has had some obvious discomfort off the field, there has been a significant demonstration of character in games. In improving to three games over .500 (24-21) for the first time this year, the team has demonstrated resilience, particularly in the most recent seven-day span, which may well prove a defining moment for the team.

The Sox suffered a brutal loss on Monday, coming all the way back from a five-run deficit against the Yankees to talk a two-run lead into the ninth, only to see closer Jonathan Papelbon blow the game in the worst performance of his career. Yet one day later, the team still had the fortitude to erase another five-run deficit against the Yanks, and this time, the Sox held on for a win.

Yet the Tuesday win came at a cost, with Josh Beckett landing on the disabled list. But the Sox were undeterred by losing their Opening Day starter, instead responding with the team’s best turn of the rotation all year. With Wakefield’ eight shutout innings on Sunday, the team received its fourth outing in five games of at least eight frames, doubling the number of starts of that length over the Sox’ first 40 contests of the 2010 season.

It has been a stretch in which the Sox have looked like a team that can compete with the league’s elite. Yet the test is not yet complete.

The Sox now have three games in Tampa Bay against a Rays team that destroyed them in Boston in April. Then, the Rays outscored the Sox 29-8, appearing vastly superior in the process.

Since that time, the Rays have continued to crush all opponents. Tampa Bay now has the best record in the majors (32-12, a pace that would translate to 118 wins) whie outscoring opponents by an incredible 102-run margin.

Yet the Sox appear to be emboldened by their recent performances. Especially after sweeping the Twins and taking two of three on the road in Philadelphia, the Sox appear to be playing with a form of conviction that had seemed absent at times this year.

“We're swinging the bats good. We're finding ways to win. We're pitching good and we're playing good defense,” second baseman Dustin Pedroia told reporters. “It doesn't really matter who we play. If we play up to our capabilities we should be able to beat teams.”

The Rays will no doubt test that proposition. But, regardless of the outcome of the next series, the Sox have made very clear that they will not shrink from the challenges that are presented to them.

Here are some other lessons of note from Sunday:

WAKEFIELD MAY NOT BE THRILLED ABOUT HIS ROLE … BUT HE’S VERY GOOD AT IT

Obviously, Tim Wakefield would prefer that he had a secure spot in the rotation, rather than requiring one of his teammates to land on the D.L. in order to know that he could take the ball every five days. The 43-year-old considers himself a legitimate major league starter, and with good reason, as evidenced by his All-Star campaign in 2009.

The knuckleballer has made no secret of his disappointment in being relegated to the role of a swing man on the pitching staff -- at least off the field. On it, however, he has been everything the Sox could have hoped from a pitcher who moves back and forth between jobs.

That was once again apparent on Sunday, when Wakefield delivered eight shutout innings to earn a long-overdue first win of the 2010 season (victory No. 190 of his career, and No. 176 with the Sox). He struck out only one batter, but elicited consistently weak contact from the Phillies lineup, recording 16 flyball outs and six groundouts.

Wakefield became the first pitcher in the majors this year to throw as many as eight shutout innings with no more than one strikeout. He became the oldest American League pitcher to throw eight or more shutout innings since fellow knuckleballer Charlie Hough accomplished the feat as a member of the White Sox in 1992, at the age of 44.

For any pitcher, it would have been a remarkable accomplishment to assemble eight zeros against a powerful Phillies lineup. That Wakefield pulled it off was all the more remarkable, for reasons that had nothing to do with the pitcher’s age.

After spending the first three weeks of the season in the rotation, Wakefield was hit hard in his first relief outing, allowing five runs in 2 1/3 innings of work. Since then, he has made three relief appearances and two starts, with a 1.69 ERA in 21 1/3 innings (1.42 ERA as a reliever, 1.80 as a starter).

Just as was the case 10 years ago, Wakefield is proving capable of success even while shuffling between roles. Even though it is not the fate that he would have chosen, the knuckleballer’s versatility has proven an asset to his club, particularly while Josh Beckett is on the disabled list. 

DOC HAS NO CURE FOR YOUKILIS

Roy Halladay has been among the best pitchers -- if not the best pitcher -- of the last decade. Armed with what some describe as the best stuff in the game, opposing hitters have hit just .254/.298/.374/.672 against him in his career.

That make what Kevin Youkilis has done against the right-hander almost startling. In three at-bats against the perennial Cy Young candidate on Sunday, Youkilis had a homer (his team-leading ninth of the year), a triple (his team-leading second of the season) and a walk (his major league leading 24th of May).

That improved Youkilis’ already tremendous numbers against Halladay. He is now hitting .375/.446/.661/1.107 against the pitcher. Against players with at least 30 at-bats against Halladay, Youkilis ranks sixth in average, fourth in OBP, second in slugging and second in OPS.

The signature confrontation between the two occurred in the sixth inning. Youkilis feel behind, 1-2, then took a ball to even the count. He spoiled a pair of tough fastballs, took another fastball just off the plate to run the count full, and then, on the eighth pitch of the at-bat, jumped on a hanging curveball, lining it into the seats in left.

It was, to be sure, a mistake by Halladay. At the same time, it was an instance of Youkilis fighting tooth and nail against good pitches to keep the at-bat alive until Halladay blinked.

“The biggest thing with him is you make good pitches, he'll foul them off," Halladay told reporters. "He doesn't really chase a lot of balls out of the zone. You have to make really good pitches in the strike zone. Even sometimes then he spoils them. You make a mistake here or there and that's when he gets you. I think that's the biggest thing. He's pretty good at knowing the strike zone. He can foul off pitcher's pitches."

Youkilis has been demonstrating that notion all month. He is now hitting .397 with a 1.391 OPS and six homers in May.

THE OUTFIELD DEFENSE IS BEING TRANSFORMED

The most illuminating moment of Jacoby Ellsbury’s first games in six weeks took place in the bottom of the seventh inning. Raul Ibanez led off the inning by smoking a liner towards left-center. Ellsbury, in his second game back from the disabled list, raced to his right and made a diving catch, holding onto the ball as he crashed to the turf.

The play was an indication that Ellsbury will not limit himself in an effort to protect his ribs as he recovers from his hairline fracture of four ribs. But it also offered a further implication.

Darnell McDonald served as an adequate place-holder in center field, but all things being equal, he is better suited to the outfield corners. With Ellsbury and Mike Cameron sidelined, the Sox featured a range-deficient outfield, particularly on days when Jeremy Hermida was in left and McDonald in center.

Ellsbury’s catch gave a glimpse of the upgrade that the Sox already achieved. Meanwhile, in Portland, Cameron offered evidence that he is nearing a return as well.

On Sunday, Cameron had his most successful day yet during his minor-league rehab assignment. The 37-year-old went 3-for-5 with a double and a walkoff homer that sent Double-A Portland to victory in 10 innings.

Cameron is now hitting .333/.406/.778/1.184 after eight minor league games while working his way back from a strained lower abdomen. He was scheduled to be re-evaluated after Sunday's Portland game to determine the next step of his rehab. The Sox have not ruled out the possibility that he could be activated during the upcoming series in Tampa Bay.  

The Sox enjoyed just six games of having Ellsbury and Cameron paired with J.D. Drew. The injuries to two outfielders who were expected to be above average -- and subsequent replacement by two who are below average -- undermined the team’s run prevention blueprint.

If Ellsbury’s play on Sunday was any indication, then the team may be primed to start correcting course.