Ovechkin played in his 983rd game, which tied Calle Johansson for the top spot in franchise history. Ovechkin already leads the franchise by comfortable margins in goals (596) and points (1,105).
When he reaches 600 goals, Ovechkin will be the 20th player in NHL history to do so. He scored twice in the third period in this game.
The victory let the Caps (77 points) jump over Pittsburgh (76) and the Flyers (76) for first in the Metropolitan Division. Florida beat the Penguins 6-5 Saturday while the Flyers were off.
Philipp Grubauer started in goal for Washington and made 28 saves, beating the Sabres for the second time this week -- the Capitals won 3-2 in Buffalo on Feb. 19.
Grubauer has now won his last three starts while No. 1 goalie Braden Holtby has gone 0-3-2 in his past five.
Andre Burakovsky and Lars Eller also scored once apiece for the Capitals in the win.
The Sabres pulled Evander Kane from their lineup with the league's trade deadline -- 3 p.m. on Monday -- approaching. The Buffalo News said a trade for Kane is "apparently imminent."
The Sabres were not helped by Washington's fast start. Kuznetsov scored 50 seconds into the game after skating through several Buffalo players and beating goalie Robin Lehner after faking him out a bit.
In the second period, Burakovsky turned in another strong individual effort with 6:40 left in the second period left that gave the Capitals a 2-0 lead.
He picked up the puck deep in Washington's end and literally worked his way through all five Buffalo players, splitting the last two before pushing the puck through the goalie's five-hole. Those two displays of speed put the Capitals on top by two goals after two periods.
Sam Reinhart cut the lead to 2-1 on a backhand shot 14 seconds into the third period.
Ovechkin then scored a key insurance goal later in the period on the power play. He took a pass from John Carlson and fired a wrist shot into the high right corner with 9:47 left.
Eller added an empty-net goal for the Capitals later with 2:12 remaining. Ovechkin then scored the fifth goal with 1:24 left and Lehner back in net.
--Field Level Media
Buffalo | Washington | |
Sam Reinhart 1 | Points | Evgeny Kuznetsov 4 |
Sam Reinhart 1 | Goals | Alex Ovechkin 2 |
Casey Nelson 1 | Assists | Evgeny Kuznetsov 3 |
N/A | Power Play Goals | Alex Ovechkin 1 |
N/A | Short Handed Goals | N/A |
Robin Lehner .886 | Save Percentage | Philipp Grubauer .966 |
Robin Lehner 31 | Saves | Philipp Grubauer 28 |
Team | Shots | Goals | Power Play | Penalty Kill | Penalty Mins | Face Offs Won |
Buffalo | 29 | 1 | 0-2 | 0-1 | 2 | 31 |
Washington | 36 | 5 | 1-1 | 2-2 | 4 | 31 |