Ovechkin scored his 497th goal, Holtby stopped 34 shots and the NHL-leading Capitals beat the New York Islanders 4-1 Thursday night.
Jason Chimera, Nate Schmidt and Nicklas Backstrom also scored to help Washington reach 63 points and become the first team with 30 wins. Holtby improved to 26-4-2, including 18-0-2 in his last 21 games.
''Our goal is to finish as high as we can in the standings to give us the best opportunity in the playoffs,'' Holtby said. ''We were definitely tested, our blocking and our protection in front of the net.''
It was the teams' first meeting since the Capitals won a seven-game series with the Islanders in the first round of the playoffs last season.
Ovechkin gave Washington a 2-0 lead with his 22nd goal of the season with 4:15 left in the first period. Islanders defenseman Adam Pelech coughed up the puck in the offensive zone and the Capitals' Karl Alzner took it and skated up the right side. He dropped it to Ovechkin, and the 30-year-old Russian wristed a shot past Halak from the right faceoff circle.
''We had a good start, that was the key,'' Backstrom said. ''We were aggressive and kept the puck in their zone and tried to work it deep in there. (It was) 2-0 after the first, that's a good way to start off the game.''
Nelson got the Islanders on the scoreboard 1:59 into the second. He took a pass from Ryan Strome in the high slot and fired a wrist shot past Holtby for his 14th of the season.
''We have to be better out of the gate,'' Islanders captain John Tavares said. ''We were a little slow to start today. There's a reason they've only lost a handful of times. ... We have to raise our level and be better.''
Ovechkin had a chance for No. 498 about 9 minutes into the second, but the puck clanged off the crossbar.
Washington restored its two-goal lead later in the period, just after killing off an unsportsmanlike conduct penalty on Tom Wilson. Backstrom dropped a backhand pass to Schmidt, and he fired a one-timer from the top of the left faceoff circle for his second of the season with 4:06 to go.
''Towards the end of the period it was really big,'' Capitals coach Barry Trotz said. ''Schmidt's goal right after the big kill there where we got some good saves by Braden. I thought we managed the game really well.''
Holtby has appeared in 33 of Washington's 40 games so far.
''He's been real solid and when he hasn't we sort of try to do the right things in front of him,'' Trotz said. ''He's prepared every night. He's a workhorse, he wants to be in the net every night and I think he gets mad when I pull him out of there. The more he plays the better he tracks the puck and the more patient he is in the net.''
Backstrom capped the scoring with an empty-netter with 2:42 remaining in the game.
Chimera put the Capitals ahead 5:45 into the game. Marcus Johansson grabbed the loose puck after taking the faceoff in the Islanders' zone, skated behind the net and passed it to Chimera, who backed up and sent a shot that deflected up off Pelech's stick and in off Halak.
NOTES: Ovechkin would be the 43rd player to reach 500 goals. In his 11th NHL season, he is already one of only six players to reach at least 50 goals a half-dozen times. The others: Wayne Gretzky, Mike Bossy, Mario Lemieux, Marcel Dionne and Guy Lafleur. ... Mike Richards met with the media before the game, a day after agreeing to a one-year deal with the Capitals. The 30-year-old center became a free agent after Los Angeles bought out the remaining five years of his contract last summer following his arrest at a Canadian border crossing in June on charges of possession of a controlled substance. ... Halak was activated off injured reserve on Tuesday after missing five games due to an upper body injury and played for the first time since Dec. 21. ... The Islanders were playing the top team in the league for the second straight day. Dallas came in with the NHL's highest point total on Sunday but lost 6-5. Washington beat Boston on Tuesday night to move into the league lead.