Adrian Gonzalez inspired awe with his performance in the month of May. But he was not the Red Sox slugger who had the best 31-day stretch.

That unofficial honor would go to none other than designated hitter David Ortiz, who has turned back the clock to perform at the sort of level that characterized his prime. The 35-year-old put his final stamp on the month of May by going 2-for-4 and slamming a homer into the Monster Seats – against left-on-left relief specialist Will Ohman, no less – in his club’s 10-7 loss to the White Sox. (Recap.)

That punctuation mark concluded a huge May for Ortiz, who led Sox regulars – yes, besting even Gonzalez – during the month in average (.342), OBP (.387), slugging (.694), OPS (1.081), homers (10), total bases (77) and extra-base hits (19). Yet beyond the numbers, it was the approach demonstrated by the DH that suggested a vintage Ortiz performance.

Tuesday night offered a case in point. Ortiz singled through the shift on a fastball from Phil Humber in the seventh. One inning later, with the Red Sox rallying against Chicago’s starter, White Sox manager Ozzie Guillen summoned Ohman to handle Ortiz.

Ohman entered the night having held his left-handed counterparts to a .208 average and .630 OPS with nine strikeouts in 28 plate appearances. But Ortiz had a textbook approach against him. After fouling off a first-pitch fastball on the inside corner, he laid off a pair of sliders down and away.

After falling behind, 2-1, Ohman threw a fastball up and away. Ortiz stayed back on it and, with an almost effortless swing, drove the ball into the top row of the Monster Seats in left-center for his 10th homer of the month.

Both the ability to stay in the strike zone against Ohman as well as the opposite-field shot represented the continuation of a season-long approach by Ortiz. Hitting coach Dave Magadan suggested that the slugger is using the whole field as well as he has at any time “since ’07. He started to kind of go away from it a little bit in ’08, and in ’09 and ’10, he only used half the field against lefties.

“He’s kind of gone back to his roots, gone back to using the whole field approach,” added Magadan. “He’s got six fielders sitting on the right side of the field. He’s taken advantage of using the whole field. He’s more than capable of doing what he did tonight – hitting a ball over the Monster against a left-hander who’s going to throw him a lot of breaking balls. He hit a fastball out, but it was getting into the fastball count and not chasing those sliders that were out of the zone to get into the fastball count and taking advantage of it that was key.”

More often than not this year, Ortiz has been executing just such an approach. He’s continued his success against right-handers, hitting .317 with a .372 OBP, .585 slugging mark, .956 OPS and nine homers. But he’s also been a force against lefties, hitting .291 with a .400 OBP, .509 slugging mark, .909 OPS, three homers and more walks (10) than strikeouts (7).

The performance represents a radical departure from a year ago, when Ortiz ended up sitting at times against tough lefties by virtue of his significant splits. He hammered righties (.297 average, 1.059 OPS, 30 homers) but could be handled by southpaws, who held him to a .222 average and .599 OPS, and he went deep just twice against southpaws.

Already this year, in just 55 at-bats, Ortiz has more homers against lefties (3) than he did in 185 at-bats in 2010 (2). It is no accident.

Ortiz came into the season intent on re-establishing his credentials as an everyday player who would not be slowed by left-handers. He’s fulfilled that ambition, resulting in big numbers (.310 average, .380 OBP, .563 slugging, .944 OPS) through the first two months of the year.

“He’s capable of doing it,” said Magadan. “Now, it’s staying with the approach. They’ll make adjustments and he’ll make adjustments back. But he’s got that attitude that he’ll use the whole field against left-handers – not just against left-handers, but against everyone. When he’s got that approach, he puts up the numbers that he’s putting up.”

Right now, the numbers that Ortiz is amassing are eye-opening. He ranks in the top five in the AL in both homers and OPS. He is on pace for 35 homers, in a year in which he’s walked (22) and struck out (22) in equal measure. (From 2007-10, only four players -- Albert Pujols (4 times), Gonzalez, Mark Teixeira and Ortiz -- have hit 30 homers in a year when they walked at least as many times as they struck out.) And he is just now arriving at the time of year in which he typically heats up, as the ball begins to carry during the summer months.

With his performance, the whispers that greeted Ortiz’ slow starts of the last two years are no longer heard. His performance is defying the signs of aging that one looks for in players as they move past their primes.

The fact that the ball is flying off his bat for extra-base hits means that he is maintaining his balance and strength, as well as his health. That so many of his hits have been to the opposite field suggests that he is not cheating – his bat speed remains good enough that he can stay back on the ball and react to the pitch where it’s thrown. And his strikeout-to-walk rate suggests that his pitch recognition has been exactly what it needs to be; while some big leaguers see their performances drop because their eyesight worsens as they age, Ortiz is giving no evidence that such a factor is a concern.

The Sox made the decision to pick up Ortiz’ $12.5 million option this offseason, even though – at a time when very good designated hitters could be found for a fraction of that price tag – the decision seemed to be rewarding the DH more for his past performance than potential future returns.

Yet Ortiz has defied that conclusion, turning back the clock in the early-going of 2011 with a performance that is nearly in line with what he did in his prime. Only once before – in 2007, when he hit .315 with a 1.009 OPS through the end of May, en route to a fourth-place MVP finish – has Ortiz had a better OPS entering play on June 1 than he has this year.

To date, Ortiz has not merely been a former superstar who is aging gracefully. He has been a middle-of-the-lineup menace who has been as good as anyone in the Sox lineup.

“He’s where he needs to be,” said Magadan.