BOSTON -- The Ottawa Senators pushed the Boston Bruins to the brink of elimination with a 1-0 victory in a tight-checking Game 4 of their first-round playoff series on Wednesday night.

The Senators, who finished second in the Metropolitan Division while the Bruins were third, can eliminate Boston on Friday night in Game 5 in Ottawa.

Craig Anderson turned aside 22 shots and Bobby Ryan scored 5:49 into the third period as the Sens made it 7-1 against Boston this season with their fifth straight victory at TD Garden dating back to last season.

Erik Karlsson's shot from the blueline was intentionally wide and Ryan, getting behind rookie Charlie McAvoy, poked the puck past Tuukka Rask and just over the goal line past a diving Zdeno Chara.

It was Ryan's third goal of the series and his fourth in five games dating back to the regular-season finale, when he broke a 13-game scoring drought.

Anderson stopped two Brad Marchand breakaways in the first period en route to his fourth career playoff shutout. He also stopped Marchand, who had six shots on goal, twice after Rask was pulled for an extra attacker.

Rask made 26 saves in the loss.

Marchand, a 39-goal scorer in the regular season who scored the winner in Game 1 of the series, has been blanked in the last three games.

The Bruins thought they had taken a 1-0 lead 10:49 into the second period when Riley Nash got the puck back to rookie Charlie McAvoy. The defenseman, playing in his fourth NHL game, beat Anderson from the right point with the help of a deflection off an Ottawa player. But a challenge of an offside committed almost 20 seconds earlier showed Boston's Noel Acciari was offside and the goal was erased.

Ottawa's Tom Pyatt left the game in the first period after suffering an upper-body injury on a check from Kevan Miller.

The loss capped a dreadful four days for Boston's two indoor teams.

With the Bruins losing Monday and Wednesday and the NBA Celtics Sunday and Tuesday, it was the fourth time in the history of the two Boston Gardens the teams had lost on four straight nights in the postseason -- only the second time they both lost twice in the four nights, according to STATS, Inc. In 1969, the Bruins lost twice to the Montreal Canadiens and the Celtics twice to the Los Angeles Lakers.

NOTES: Boston D Colin Miller returned after missing the first three games of the series with a lower-body injury, while D Tommy Cross, who made his playoff debut in Game 3, was scratched. ... Ottawa coach Guy Boucher said D Mark Borowiecki "is getting closer every day" but Borowiecki missed his second straight with a leg injury, the Sens lineup remaining the same. ... The overtime wins in Games 2 and 3 marked the first time in franchise history Ottawa has won back-to-back games in OT. ... Bruins C Patrice Bergeron is a finalist for the Selke Trophy (best defensive forward) for the sixth straight year. He has won the award three times.