His team came up on the short end of a 5-3 defeat to the White Sox to lose the series, but Papelbon passed with flying colors -- red, white and a shade of blue.
"He did a fantastic job," Red Sox general manager Theo Epstein said. "We take him for granted. He's a young guy in a big spot. He performed really well."
Pitching in relief of Red Sox starter Tim Wakefield on Friday, behind left-handed specialist Mike Myers and right-handed specialist Chad Bradford, Papelbon entered the game in the sixth with the White Sox leading, 4-2. He did not allow a hit and struck out two batters in 2 2/3 innings. The Red Sox would cut the lead to one run with a home run by Manny Ramirez in the sixth, but they would not get any closer.
The offseason starts now for the Red Sox and Papelbon.
"He kept us in the game and we just couldn't get that extra run," Red Sox first baseman Kevin Millar said. "What more could you ask from him?"
Not much. Including his appearance in Chicago in Game 2 of the ALDS when he allowed two hits in 1 1/3 innings, Papelbon pitched four scoreless innings in the series.
How? By being a quick-study.
"I learned [that] it's a different situation, but you have to stay cool and trust your stuff and ability and not let the atmosphere take over," Papelbon said. "Basically, [the White Sox] did everything right and they played error-free ball and they did everything right at the key moments. Unfortunately for us, we were unable to stop them."
Papelbon said a key to his success during the playoffs was confidence. Confidence by his teammates and confidence in himself. The tall Louisiana native is a polite gentleman. He's also tough as nails.
"I knew that I could go out there and get guys out," Papelbon said. "I knew I could keep the ballgame there and that's all my mindset was. I was hoping our lineup would come through, but, unfortunately, they made some great plays out there. When they are playing great defense and pitching great, it's tough to beat that."
Papelbon's recent performances surprised only a few -- if anyone. He recovered from a slow start in the bullpen this season and went on to post a 1.35 ERA in 13 1/3 innings in September for the Red Sox. The right-hander, who started the season at Double-A, made three starts for the Red Sox earlier in 2005 and finished the regular season 3-1 with a 2.65 ERA in 34 innings.
The ride in 2005 was nice. The sudden stop -- not so nice.
"I think the whole year from Double-A to Triple-A to the big leagues was all a big learning experience," Papelbon said. "It was a big point in my career where I can take all of this and put it underneath my belt with the experience and everything I did. Hopefully, I will be able to learn from everything this year and take it into next year."
Papelbon admitted there were too many lessons learned in 2005 to point out, but only one that will stick with him the most. When pressed, he stressed the importance of modifying his approach on the fly and not being afraid.
"The main thing I learned is you have to make adjustments," he said. "When they are making their adjustments against you, you have to do the same against them. That was a big key for me this year."
The pitcher's future is bright. Papelbon is happy pitching out of the bullpen in the middle of games, but would be happier to be running out of the bullpen and starting them.
"Whatever [Red Sox manager Terry Francona] needs me for, I will be willing and able to do," he said. "We'll see what happens going into the offseason and we'll see what happens during Spring Training. ... I love pitching here and I love the fans here. I hope I will be able to pitch here for a long time."
Jesse Sanchez is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.