Ovechkin equaled the record of Dave Andreychuk with a goal at 3:36 of the second period.
The 36-year-old forward is in his 17th NHL season and played his 1,226th game. He had not scored a power-play goal in seven games, since Nov. 26.
"It's going to be a very interesting moment for me and, I think, for the League just to get this (record) and be No. 1," Ovechkin said in November.
Ovechkin has scored five power-play goals among his 21 goals this season. Nicklas Backstrom had an assist on the goal playing his first game of the season after recovering from a hip injury. The center has an assist on 115 of Ovechkin's power-play goals.
The Capitals lost 5-4 in overtime.
"I don't know much more there is to say. everyone sees and says the same thing," Washington coach Peter Laviolette said. "You know what's great about 'Ovi'? That game-tying goal (an assist to Conor Sheary with three seconds remaining), you see his emotion in the game, and that's what makes him special. You know what I mean? He loves the game of hockey. So to fight back and get a point and tie that up, you go back and you watch that, you see how excited he is that he was able to help contribute in a way to get his team back to even and force an overtime. But it was a nice power-play goal set up by a lot of people and certainly finished by him."
Ovechkin scored on a one-timer from the left face-off circle; he has scored 111 power-play goals from inside or above the circle.
"We looked at our [penalty kill] and you break it down for them: One, two and three, who's the most dangerous?" Chicago coach Derek King said. "And obviously he's the most dangerous. But it's just the way it is. ... Even back when I was playing ... these guys can shoot the puck and you would try to defend them but they'd find ways to score goals. This is what happens when, I don't know how many goals he's got now, 700? I think you lose track after 100. He's a good player."
Andreychuk retired in 2006 after playing 1,639 games in 23 NHL seasons.
"If he continued to stay healthy, and wanted to play, he was eventually going to go by me," Andreychuk said this season. "So when that day comes, I had a good run. Let's just say that. It's been a while. It's been fun. And to be put in that same class, as Phil Esposito (sixth with 246), Brett Hull (third with 265), and now Alex Ovechkin, I'm so very honored."
Ovechkin scored NHL goal No. 750 on Dec. 4 in a 3-1 win against the Columbus Blue Jackets and has scored 751 goals, fourth in NHL history behind Jaromir Jagr (766), Gordie Howe (801) and Wayne Gretzky (894).
Andreychuk scored 640 goals (15th in history) in 1,639 games with the Buffalo Sabres, Toronto Maple Leafs, New Jersey Devils, Boston Bruins, Colorado Avalanche and Tampa Bay Lightning.
NHL.com staff writer Tracey Myers contributed to this report
