Mike Hoffman scored a power-play goal to break a tie midway through the third period, and the Ottawa Senators rallied from a pair of deficits to post their fifth straight win, 4-2 over the reeling San Jose Sharks on Saturday night.

Hoffman added an empty-net goal, and Erik Karlsson and Mark Stone also scored for the Senators, who completed a California sweep. Andrew Hammond followed up shutouts in Anaheim and Los Angeles by stopping 28 of 30 shots to win his fifth straight start to open his career.

Tommy Wingels and Patrick Marleau scored for the Sharks, who have dropped eight straight home games for the first time since the 1994-95 season to put their streak of 10 straight playoff appearances in doubt. Antti Niemi made 27 saves.

The Sharks' last two losses came in games they led after two periods, also blowing a 2-1 lead Thursday night in a 3-2 loss to Detroit.

San Jose had lost just once in regulation all season when leading after two periods before doing it twice in three nights. That marked the first time in franchise history the Sharks lost consecutive games in regulation that they led after two periods, according to STATS.

Trailing 2-1, the Senators took over the game with a pair of goals in a span of 4:07 early in the third period. Stone got the equalizer when he beat Scott Hannan to a rebound of a shot by Kyle Turris less than 4 minutes into the period.

Then with Brenden Dillon in the box for tripping, Hoffman put Ottawa on top for the first time when he knocked in a rebound of Mike Zibanejad's shot off the end boards.

The Sharks barely threatened the rest of the way, and Hoffman iced it with his empty-netter with 1:10 to play.

Hammond's bid for the California shutout sweep ended early against the Sharks. Coach Todd McLellan juggled his lines in an effort to spark his team and it paid off when the reconfigured third line got on the board just 2:27 in.

Matt Irwin put a shot on goal, and Wingels knocked in the rebound during a scramble in front of the net for his 13th goal. Hammond was less than 10 minutes from breaking Patrick Lalime's club scoreless streak of 184:06.

Hammond still played well, stopping Logan Couture on a breakaway before the Senators found their legs late in the period. Niemi kept them scoreless with a pad stop on a rebound attempt by Matt Puempel in the final minute of the period.

The teams then traded power-play goals in the second with Karlsson tying the game early in the period when he retrieved Kyle Turris' shot off the end boards and beat an out of position Niemi for the goal.

The Sharks answered late in the period when Marleau knocked in the rebound of Brent Burns' point shot to score on the power play for the second straight game. Marleau had just one power-play goal in the previous 46 games.

NOTES: Ottawa had been 0-for-11 on the power play the previous three games before scoring twice vs. San Jose. ... The Sharks activated F Tye McGinn from IR and sent Chris Tierney to the minors.