Ovechkin had the second two-goal performance of his career on an opening night -- he made his debut in 2005 with a pair of goals in Washington's 3-2 win at Columbus. Ovechkin had only one assist in his other three season-openers.
"If you give him too much time to shoot, he will make you look bad," Bruins defenseman Dennis Wideman said. "He is the hardest-working and hardest-hitting superstar in the league. He is the Rafael Nadal of hockey, and (Sidney) Crosby is (Roger) Federer."
It was a disappointing opener for the Bruins, who started the season at home for the first time since 2005 and were coming off a 116-point season that put them first in the Eastern Conference. Boston was outshot 34-20, including 12-3 in the third period, and didn't beat Jose Theodore until Patrice Bergeron scored on a backhander 7:56 into the third period -- but by then, the Capitals had a comfortable 4-0 lead.
It was the Caps' first regulation win in Boston in 14 tries since Dec. 2, 2000.
"If you could bottle that game up, we'd take it," coach Bruce Boudreau said. "Every night."
Laich scored the first goal of the NHL season 17:15 into the game, finishing off a perfect three-way passing play. Ovechkin fed Nicklas Backstrom, whose perfect pass found Laich all alone for an easy tap-in past Tim Thomas.
Ovechkin, who led the NHL last season with 56 goals, made it 2-0 at 9:31 of the second period on another nice passing play. This time, Backstrom fed Alexander Semin in the Washington zone and Semin slid the puck to an onrushing Ovechkin as he raced down the slot. Ovechkin rifled a slap shot from between the circles past a helpless Thomas.
"They pushed on us hard," Ovechkin said. "We played great defensively in the second period and we made that push and bounced back. That second goal was big."
The Caps blew the game open in the first two minutes of the third period. Laich scored his second power-play goal by knocking in a rebound just 16 seconds after the opening faceoff and Ovechkin added his second of the night on a snap shot from between the circles at 1:56.
Bergeron's goal just as Marco Sturm's penalty expired served only to spoil Theodore's bid for his 29th career shutout.
"We had too many good players probably at their worst," Bruins coach Claude Julien said. "You don't want to take credit away from (Ovechkin), but you also want to expect more of your players, especially when he's on the ice."
Boston dropped to 28-14-11 when opening the season at home and 35-34-16 all-time. The Capitals improved to 17-16-2 all-time in openers and 6-11-2 when they play their first game on the road.
Julien promised improvement -- and soon.
"This is not the same team you're going to see on the ice night after night. That I can guarantee," Julien said. "As a home opener, it's certainly not what you want to demonstrate. We have a chance to redeem ourselves soon. Hopefully the guys take advantage of that."
--John Kreiser, NHL.com
Material from wire services and team media was used in this report