Patrice Bergeron tied the game in the third period, then beat Kolzig again in the shootout as the Boston Bruins overcame a three-goal deficit to beat the Capitals 4-3 and send them to their ninth consecutive loss. That spoiled Chris Clark's hat trick and Kolzig's return after missing 13 games with a left knee injury.
"He's probably the most important player to that team," Bruins goalie Tim Thomas said after stopping 31 shots. "He's the only reason they were in the game after the first period, and that they got to the shootout."
Clark scored a short-handed goal with 2:57 left in the second to complete his second career three-goal game and give the Capitals a 3-0 lead. But the Bruins tied it, thanks to three assists from Marc Savard and power-play goals 65 seconds apart in the third after Washington spotted them a 5-on-3 advantage.
It stayed that way until the first three skaters missed in the shootout. Bergeron went between Kolzig's legs and Alexander Ovechkin scored on a backhand before Phil Kessel scored the winner.
"Kessel's a talented kid and put on a great move. But I was thinking too much," said Kolzig, who stopped 36 shots. "He did the same thing he did to me in Washington, and I need to be smarter than that."
Washington is 0-6-3 in its last nine games after going 1-8-4 without Kolzig, who appeared to re-injure himself on the last shot of the overtime - a slapshot by Zdeno Chara off his right knee. Kolzig returned for the shootout after stretching his legs during the break.
"The biggest man in the league gets a shot on your bare knee, it's going to hurt," Kolzig said.
The Bruins swept the season series against Washington but needed overtime in each game to do it. The Capitals have not won in Boston since 2000 and haven't beaten the Bruins in regulation in 10 games overall.
Boston is in 12th place in the Eastern Conference with 12 games to play. Washington is in 14th and out of playoff contention.
"Considering the situation, it doesn't get any better than this," Boston coach Dave Lewis said.
Clark made it 3-0 just 15 seconds after teammate Tomas Fleischmann went off for holding. But the Bruins ended the shutout bid 79 seconds later when Marco Sturm converted on some crisp cross-ice passing to make it 3-1.
Washington's Shaone Morrisonn and Steve Eminger were called for penalties in the last minute of the second, and the Bruins took advantage when Brandon Bochenski and Bergeron scored to tie it.
Alexander Semin missed a backhander on an open half of the net, hitting the post with about a minute left in regulation. With 40 seconds remaining, Boyd Gardner was called for an off-balance slash at Dennis Wideman's face, giving the Bruins a rare overtime power play.
But Kolzig stopped Chara on at least three slapshots from the right circle, the last as time expired. Kolzig snapped his head back when he made the final save, then sprawled onto the ice. During the break before the shootout, he waited at the Washington bench, flexing his knees.
Savard has seven assists in three games and nine against the Capitals this season. He has 70 for the season - the most for a Bruins player since Adam Oates had 80 assists in 1993-'94.
Notes: After Andrew Alberts and Matt Bradley mixed it up midway through the second, Chuck Kobasew got the best hit of all when he checked Morrisonn into the Capitals bench. ... Washington also had an eight-game winless streak last March. ... Ovechkin, who entered the night tied for third in the NHL in goals, has just one in four games against the Bruins. ... The Capitals have 12 short-handed goals, four by Clark.