At the start of the series between the Toronto Maple Leafs and the Washington Capitals, it was the Stanley Cup contender without any discernible holes versus the young kids who should be happy just to be there.

That’s not how it played out. At all.

The Maple Leafs proved they were up to the task against a team built to win it all now, and the expectation should be that they’ll join Washington and Pittsburgh among the favorites to win the East next season. That’s how good they looked. That’s how bright the future is in Toronto. That team is on an impressive trajectory.

But first, GM Lou Lamoriello has some tweaking to do in order to get the Maple Leafs to the next level, starting here:

1. Add a top-four, skilled defenseman

The Leafs are in a bit of a sweet spot right now. They have a small window during which Auston Matthews, William Nylander, Mitch Marner and Kasperi Kapanen are on their entry-level contracts, earning significantly less than what they’re worth.

The goal should absolutely be to win a Stanley Cup before Matthews moves on to his second contract in 2019-20 -- like the Chicago Blackhawks did with Jonathan Toews and Patrick Kane in 2010, the final year of their entry-level deals. With some help on long-term injured reserve, Toronto should have cap flexibility in the short term this summer. The challenge is that any big contract they add this summer is likely going to span into the years during which their young stars will need to get salary increases. That would be the scenario if they pursued a free agent like Kevin Shattenkirk, who surely isn’t signing a two- or three-year deal.

Maybe the better solution would be to move a forward, like James van Riemsdyk, in a deal that brings a defenseman back on a contract that doesn’t extend too far into the future.

These playoffs were great experience for guys like Morgan Rielly and Jake Gardiner, who played well. But even so, the Leafs could use an upgrade on defense.

2. A contract extension for Nikita Zaitsev

Toward the end of the season, it sounded like the two sides were close on a deal that would keep Zaitsev in Toronto for the next seven years on a deal worth north of $4.25 million per season. The playoffs became the focus, and once he returned to the lineup, he averaged more than 20 minutes of ice time per game against the Capitals.

The priority should be getting his new deal done quickly, so the Maple Leafs can focus on filling in around him, Gardiner and Rielly.

3. Shore up the backup goalie spot

Mike Babcock tends to ride his starting goalie if it’s going well, and that was the case with Frederik Andersen this season. He started 66 games for the Maple Leafs, 13 more than the previous heaviest workload of his career. Andersen was good for the Leafs, leveling out right at his career average of a .918 save percentage after a slow start.

However, when he was injured at the end of the season, panic set in -- a sign of how reliant the Maple Leafs are on Andersen. Curtis McElhinney, the current backup, is a pending unrestricted free agent, and if the Leafs can upgrade without spending too much, it would be a wise investment. The difference between missing and making the playoffs in today’s NHL can sometimes hinge on contributions coming from the backup netminder.