Moved up to Ovechkin's line, Clark scored his first two goals Wednesday night, and Washington's juggled lineup produced the team's biggest scoring output of the season in a 5-3 victory over the Tampa Bay Lightning.
Ovechkin contributed two assists and an empty-net goal with four seconds left to help the Capitals end a four-game losing streak and drop the Lightning to 0-3 on the road for the first time since 2000.
Washington was averaging only two goals per game entering Wednesday's action, but had more success against Tampa Bay goalie Marc Denis, making his first start this season.
The Capitals also entered the day as one of only two clubs in the NHL that had yet to score more than three goals in a game, a drought that extended 16 games to a 7-1 victory over Tampa Bay on March 18 last season.
Capitals coach Glen Hanlon shifted around his forward lines, in part because he was able to use wing Alexander Semin, who came off injured reserve after missing six of seven games because of a sprained right ankle.
Hanlon also changed right wing Clark from a checking line to the top line, joining left wing Ovechkin and centre Viktor Kozlov. It didn't take long for that to work out.
Just 6:33 into the game, Ovechkin corralled a poor clear attempt by Tampa Bay's Shane O'Brien and made a backhand pass to Clark, who quickly flipped a shot under the crossbar for his first point this season.
Clark played with Ovechkin often the previous two seasons and scored a career-high 30 goals in 2006-07.
After Tampa Bay tied it 1-1 on Jason Ward's first goal of the season about 16 minutes into the first period, Ovechkin set up David Steckel's first career goal a little more than 4½ minutes into the second period to make it 2-1.
Kozlov passed to Ovechkin, who threaded the puck past three Lightning players in front of the net and over to Steckel on the right side. After the puck went in, Ovechkin skated over to meet the rookie behind the net with a pat on the helmet and a yell of, "Yeah, baby!"
The Lightning evened things again three minutes later with a short-handed goal. A mere 13 seconds into a Washington power play, Semin turned the puck over, and Tampa Bay rushed the other way, with Ward and Brad Richards setting up Paul Ranger.
That 2-2 score didn't last, though, because Washington scored twice in 61 seconds. First, Brooks Laich put the Capitals back in front with 2:19 left in the second period. Then, Clark knocked in a rebound off Brian Pothier's shot to make it 4-2.
The Lightning narrowed the gap when Martin St. Louis put a shot past goalie Olie Kolzig with 5:54 left off assists from Vaclav Prospal and Mathieu Darche. But with Denis lifted for an extra skater, Ovechkin scored his team-high fifth goal.
Notes: Lightning C Vincent Lecavalier fought with Capitals D Shaone Morrisonn with about 14½ minutes left, and Lecavalier was given two minutes for slashing, two minutes for instigating, five minutes for fighting plus a 10-minute game misconduct. Morrisonn got five minutes for fighting. ... Denis went 3-0 against Washington last season.