Auston Matthews scores a third-period goal after getting free from Capitals defensemen Dmitry Orlov and Matt Niskanen. (Nick Wass/Associated Press)

Toronto center Auston Matthews was lurking beside the right post when the puck took a bounce in the crease and landed on his stick. He turned and flicked it across the goal line, pumping both fists as he bent at the waist and roared. The red goal light flashed, and the night officially belonged to the Maple Leafs.

The night had been an entertaining chess match between teams expected to be among the NHL’s best. On one bench, the defending Stanley Cup champion Washington Capitals. On the other, the Maple Leafs, a trendy pick to claim that title this season. It came down to the third period, when Toronto was better and Washington got sloppy, and so the Maple Leafs won Saturday night’s early-season measuring-stick game, 4-2, as the Capitals lost their second game in a row.

“It was a pretty evenly matched game,” Washington goaltender Braden Holtby said. “They seemed to get a few breaks, and we kind of didn’t seem to get those — a bunch of open nets that just didn’t seem to go our way. But there are still areas there that I think we’d like to just keep improving at. It was a good test, obviously, but we know we have more.”

After forward Par Lindholm tipped in the game-tying goal with 1:07 left in the second period, Toronto controlled play to start the third. Defenseman Michal Kempny clipped center John Tavares with a high stick, giving the Maple Leafs a power play. Forty-one seconds later, Josh Leivo gave Toronto its first lead. Matthews delivered the final cushion with less than two minutes left for his 10th goal of the young season.

“The first 10 minutes of third period, we [were] kind of sloppy a little bit,” Capitals center Evgeny Kuznetsov said. “I don’t know why we [made] those mistakes, but then they got that goal.”

Maple Leafs goaltender Frederik Andersen gets in front of a shot from Capitals captain Alex Ovechkin in the second period. (Nick Wass/Associated Press)

This was expected to be a high-scoring affair; Toronto had scored 25 goals in its first five games, and Washington had 18 goals in its first three before getting shut out by the New Jersey Devils on Thursday night. On Saturday’s first shift, captain Alex Ovechkin collected the puck in the Capitals’ defensive zone and flung it up the ice, where Kuznetsov got it for a two-on-one with Chandler Stephenson. Maple Leafs goaltender Frederik Andersen stopped Kuznetsov’s shot, but Stephenson knocked in the rebound to lift the Capitals to a 1-0 lead just 18 seconds in.

With right wing Tom Wilson suspended for the season’s first 20 games, pending an appeal, Washington has had to replace his presence on the top line. Brett Connolly played there for the first four games, but with his team coming off a 6-0 loss Thursday, Coach Todd Reirden decided to make a change. He promoted Stephenson to the right side of Kuznetsov and Ovechkin; the only other time the trio had played together was in the clinching Game 6 win against the Pittsburgh Penguins in the second round of last season’s playoffs.

“Obviously, the start was great, but they did a number of good things during the game as well,” Reirden said. “So I thought they accomplished a lot. I thought [Stephenson] brought the speed on the forecheck and was able to at least go after their defense a little bit and force some turnovers. Kuznetsov and Ovi were able to at least get some opportunities from that. . . . We’ll continue to try to put together four lines that give us the best chance.”

The game settled into a tight-checking rhythm after Stephenson’s goal, but Toronto broke through when Kasperi Kapanen deflected Ron Hainsey’s point shot early in the second period. Sixty-nine seconds later, Washington was back up. The Capitals were awarded a power play when Tavares tripped Ovechkin, and after Kuznetsov collected a pass from Nicklas Backstrom behind the goal line, he stickhandled up to the net, keeping his eyes on forward T.J. Oshie in the slot. Without looking at the net, Kuznetsov placed a shot over an unsuspecting Andersen’s shoulder for his fourth power-play goal in five games.

Toronto’s Auston Matthews and Patrick Marleau celebrate late in Saturday’s game in Capital One Arena. (Patrick Smith/Getty Images)

“I looked for the pass, but then I don’t know what happened,” Kuznetsov said. “I decide to shoot, and I think that’s pretty lucky shot.”

Toronto made arguably the biggest splash of the summer by signing Tavares, giving it impressive center depth that now rivals Washington’s. The Maple Leafs came to Capital One Arena with plenty of hype, an early-season Stanley Cup favorite even as the Capitals returned nearly their entire roster. What was ultimately frustrating for Washington was that it contained Toronto’s superstars for most of the game but still fell short.

“I felt like, through the first two periods, we carried the majority of the chances,” Reirden said. “I loved our start to the game. You’ve got to play a full 60 minutes in this league against the teams that are the top teams in the league, especially ones that are that dangerous offensively. It just came down to some poor execution through the neutral zone that allowed them to start to get some momentum in the game.”