BOSTON -- Maple Leafs head coach Mike Babcock used the word "opportunity" over and over again when discussing his team's playoff rematch with the Boston Bruins.

Toronto wound up missing a big one against its Atlantic Division rival.

The Leafs lost in seven games for the second consecutive season on the same TD Garden sheet of ice Tuesday night.

There were points in the back-and-forth series when Boston was there to be had, but time and again, Toronto was unable to capitalize.

The margins were small, and in the end the Bruins did enough to get past the Leafs and send them on another long summer as Toronto's Stanley Cup drought officially reached 52 years.

The Canadian Press takes a look at some of the elements of the series from a Leafs perspective that, if different, could have seen them move onto the second round of the playoffs for the first time since 2004.

KADRI SUSPENSION

The Leafs won the series opener in convincing fashion and were heading home with a split in the dying moments of Game 2 when Toronto centre Nazem Kadri cross-checked Boston forward Jake DeBrusk -- retaliation for a clean hit on Patrick Marleau. The NHL suspended Kadri, who was banned three games for boarding last spring against the Bruins, for the rest of the series. Apart from missing one of their grittiest players, Kadri's absence forced the Leafs into playing William Nylander at centre on the third line instead of having the option of moving up him up on the wing alongside Auston Matthews if need be.

SPECIAL TEAMS DISASTER

The clubs were basically a wash at 5 on 5, but the Bruins dominated on the power play and penalty kill. Boston finished 7 for 16 on the man advantage, while Toronto scored just three times on 16 chances. The Bruins wore out their No. 1 unit featuring Brad Marchand, Patrice Bergeron, David Pastrnak and Torey Krug, while the Leafs often swapped out theirs led by Matthews, Mitch Marner and John Tavares in favour of the second group after roughly a minute. Toronto's look was also predictable until Game 7, when Matthews and Marner switched sides on the setup. Boston's power play scored twice with the Bruins' backs against the wall in Game 6, while the Leafs were a combined 0 for 5 in the final six periods of the series.

GAME 7 BLUNDERS

All three of Boston's goals before the two empty netters that sealed it in Boston's 5-1 victory in Game 7 were preventable. Travis Dermott turned the puck over on the opener, but Frederik Andersen had to make the save on the short side. Jake Gardiner, who was a disastrous minus-5 in Game 7 in 2018, made another horrendous blunder that Marcus Johansson capitalized on to make it 2-0. Then with Toronto down 2-1 early in the third period, Tavares turned the puck over in the neutral zone, and Ron Hainsey and Morgan Rielly were caught flat-footed before Sean Kuraly snapped a shot from 40 feet out that Andersen needed to stop.

STARS FALL

While the line of Tavares, Marner and Zach Hyman did a good job neutralizing Bergeron, Marchand and Pastrnak at 5 on 5 when they were out together, too many of Toronto's stars were unable to break through offensively as the series wore on. Tavares scored for the Leafs in Game 7 to make it 2-1, but that was his only goal apart from an empty netter. Marner had just one point at even strength, and none after Game 4, while Nylander, who was put in a difficult position with Kadri suspended, scored his only goal in the opener. Matthews led Toronto with five goals in the series after a slow start, but it wasn't enough to get his team over the hump. A stud in each the Leafs' victories, Andersen needed to be better in Game 7. He faltered badly on two of the three goals he allowed.

BABCOCK'S STUBBORNNESS

While the Leafs coach tried to mix things up in Game 7 with a wrinkle on the power play, Babcock was slow to react to the changing dynamics of the series -- unlike Bruins counterpart Bruce Cassidy. Toronto's penalty kill often failed to gain possession off defensive-zone draws without a true centre on the ice, while Boston managed to pick apart the Leafs' systems, especially in Games 4 and 6. Babcock also didn't play Tavares or Matthews nearly enough in Game 7 with his team trailing most of the night, while consistently rolling out the 39-year-old Marleau at key moments despite the speed of the matchup being clearly beyond him.

NO KILLER INSTINCT

The Leafs led the series 1-0, 2-1 and 3-1, but never put their boot on the Bruins' throat. In Games 4 and 6, massive chances were wasted. Toronto could have gone up 3-1 in Game 4 on home ice, but were sluggish before a late rally in a 6-4 loss. Then with a chance to close the Bruins out at Scotiabank Arena in Sunday's Game 6 following a masterful road performance in Game 5, the Leafs started well, but wobbled when the Bruins fought back with two power-play goals and were unable to mount a response until the opportunity was out of reach.