They have wobbled, stumbled — and even taken a few steps backward over the past six months, but your 2009-10 Bruins have now triumphantly shaken hands at center ice with a defeated foe and moved on to the second round of the playoffs.

With David Krejci scoring two goals, Mark Recchi and Mirsolav Satan providing single tallies and Tuukka Rask making 27 saves, the sixth-seeded Bruins eliminated the third-seeded Buffalo Sabres with a 4-3 victory before a raucous crowd at TD Garden Monday.

You may not have seen it coming, but for just the third time in 16 years the Bruins have advanced past the first round of the playoffs. Moreover, for the first time since 1992 the oft-maligned B’s have managed to get out of the opening round in consecutive years.

“It’s a nice feeling to be going to the second round,” Bruins captain Zdeno Chara said. “Buffalo was playing extremely well, they battled hard. It was a tough series.”

Boston will now await the outcome Wednesday’s Game 7 between top-seeded Washington and eighth-seeded Montreal. If the Caps prevail, the B’s will take on Sidney Crosby and defending champion Pittsburgh in the conference semifinals. Should the Canadiens upset the Caps, the Bruins would have home-ice advantage against the Flyers in a second-round matchup.

Any thoughts of getting past the Penguins would have been greeted with considerable skepticism through most of the regular season, but the Bruins' play of late raises some interesting questions.

What if Rask continues to play as well as the elite goalies in the league? Just how good can the Bruins be?

Aside from putting up league-best statistics during the regular season, Rask outdueled likely Vezina Trophy winner Ryan Miller during the opening round. He helped secure Monday’s win by making several sprawling saves as the Bruins looked to lock up the series.

“He played well, he made some really big saves for us, especially in the second period,” said Chara. “He was a big factor.”

The Bruins opened the scoring for the first time in the series, as Krejci deflected in a slick pass from Recchi in the low slot during a power play 13:39 into the first period. Recchi then swatted in a pass from Krejci early in the second and it was 2-0.

The Sabres cut into the advantage as Patrick Kaleta finished a perfect cross zone tic-tac-toe bit of passing in the second period, but Krejci netted his second goal and Satan added an insurance goal that turned out to be crucial as Buffalo drew within 4-3 and further tested Rask with just 1:13 to play.

The rookie goalie did his part to secure the series clincher, leaving Bruins fans with more optimism about the B’s playoff hopes.

“Everyone was going tonight, besides two mistakes where they scored, everyone was going, we made plays — it was a great game,” Rask said.

What if Rask and the Bruins’ league-leading defense is able to neutralize Crosby and superstar teammate Evgeni Malkin? Or to contain the Flyers attack?

What if the special teams that were clicking against Buffalo continue to excel? How good can the Bruins be?

While Boston penalty killers were extinguishing all 19 Buffalo power-play chances in the series, the Bruins power play clicked at an outstanding 27.3 percent rate of success against the Sabres, generating six goals in 22 chances.

The first two Boston goals Monday were scored with a man advantage, and the B’s had at least a power-play tally in four of the six games.

“I think our power play was a little bit better than theirs,” Recchi said when asked what he thought made the difference in the series. “That helped — our penalty killing, special teams was a big part of it. Tuukka was terrific and everyone stepped up.”

The 42-year-old Recchi certainly did his part, too, skating like a 20-year-old throughout the opening round. He punctuated an outstanding series against Buffalo by making a brilliant pass to Krejci for the Bruins' opening goal Monday. In the second period, he tapped in a feed from Krejci for his third goal and fifth point of the series.

Aside from Recchi, other Bruins forwards seemed to shake off their regular-season scoring woes. Michael Ryder chipped in two goals. Krejci had three goals and five points in the series. Satan found his scoring touch. Milan Lucic provided key assists on the final two Bruins goals Monday.

What if the B's offense has woken up in time for a solid playoff run?

They were nothing special during the regular season, but these Bruins now have been as successful as any other B’s team over the past 16 years. And they’re not done.

“We had a couple of inconsistent games at the end of the year, but for the most part for the last month we were a pretty good hockey club and a tough team to play against,” Recchi said. “It took us a long time to find that competitive edge every night and be willing to do it every night. We did it for the most part in this series and that’s why we ended up winning.”

No question about it.