Unlike their first-round series against the Toronto Maple Leafs where they were on the other end of a three games to one series lead, the Boston Bruins dug themselves too big of a hole against the Tampa Bay Lightning in Round 2.

In their first attempt to close out the series, the Lightning overcame David Krejci’s first-period tally and scored three unanswered to close out the second round series with the Black and Gold. Tampa’s 3-1 victory propels them to its third Eastern Conference Final appearance in four seasons.

Here is what we learned as the Bruins still took a step forward following last year’s first-round exit.

A bitter pill to swallow for Brad Marchand

Brad Marchand back at it, low bridges and licks Ryan Callahan in Game 4: https://t.co/n6OzzAAXCJ pic.twitter.com/qYJUB4XgMR

— Brady Trettenero (@BradyTrett) May 5, 2018

Eight points (one goal and seven assists) in five games are still worthy of a good series, but Marchand picked the worst time for his worst performance of the postseason.

Of course, it’s hard to single anyone out here, but Marchand, in particular, is worth noting especially after licking Ryan Callahan in Game 4. Yes, licking and Brad Marchand go hand in hand, and it caused the NHL to give a stern warning, again, to the Bruins’ winger.

With Marchand and GM Don Sweeney hearing from the league, head coach Bruce Cassidy hoped his talented, but edgy forward could still get under the Lightning’s skin, but in a good way heading into Game 5.

“If part of his MO is to annoy people, find another way to do it. That’s basically what’s in front of him now. …preferably by scoring some goals,” Cassidy told reporters prior to Game 5 at Amalie Arena. “That would be the best way probably.”

Marchand didn’t score a goal in Game 5. He didn’t even have a shot on goal during his 23:46 of ice time.

Still, there’s no denying that the three-time 30-goal scorer is an important cog to the Bruins’ cup chances going forward. Marchand, Patrice Bergeron and David Pastrnak had their frustrations against the stout-Lightning D, but are still one of the better trios in the National Hockey League. That can only bode well for Cassidy and company, but there’s no denying that the B’s bench boss would love to see his talented forward be a little less edgy starting next season.

Miller gives Bolts the lead shortly after a head-on-head hit collision with Backes

Great movement by the Lightning and no movement by the Bruins. JT Miller makes it 2-1 pic.twitter.com/XnH6RGqGen

— Pete Blackburn (@PeteBlackburn) May 6, 2018

Say what you want about J.T. Miller’s hit on David Backes in the second period. It wasn’t dirty, but rather an unfortunate head-to-head collision that forced Backes to leave the game. Maybe the refs — during another inconsistent performance — could’ve handed Miller a two-minute minor but beyond that would’ve been harsh.

Backes’ departure didn’t help the Bruins and their shorthanded bench for the second straight game. Well, like Dan Girardi’s overtime winner in Game 4 minutes after Torey Krug left the game with a lower-body injury, Miller came back to haunt the Bruins with the go-ahead goal and his second of the postseason with six minutes left in the second period.

#GoBolts JT Miller’s hit on #NHLBruins David Backes that has Backes down for a while pic.twitter.com/jmskomk5dz

— Boston Bruins on CLNS (@BruinsCLNS) May 6, 2018

5-on-5 woes rear their ugly head in Game 5

The one common theme in the last three games was the Bruins’ lack of execution at 5-on-5 play.

Krug’s third of the postseason at 15:58 of the third period in Game 2 marked the Bruins’ last 5-on-5 goal. Boston went the last 187:20 without an even-strength tally, while the Lightning lit the lamp eight times at 5-on-5 — including a pair of empty-netters — in that span.

From disrupting shooting lanes to establishing puck possession and disrupting the Bruins’ outlet passes, the Lightning found their formula following their 6-2 loss in Game 1. That strategy can only bode well for them against Alex Ovechkin and the Washington Capitals or Sidney Crosby, Evgeni Malkin, Phil Kessel and the rest of the Pittsburgh Penguins in Round 3.

The future is still bright in Boston

The Bruins exceeded expectations in Cassidy’s first full season. Is that a crazy statement on May 6, 2018? Sure. It would have sounded crazier in September 2017 where preseason prognostications had the Bruins anywhere from a fringe playoff team to ninth, tenth or eleventh in the East.

The Black and Gold simply faced a better team in Round 2. Maybe things are a little different if Krug plays in Game 5, or if Brandon Carlo doesn’t miss his second consecutive postseason because of injury.

They have a lot to be proud of, though. From Charlie McAvoy and Jake DeBrusk sparking the youth movement to Marchand, Bergeron and Pastrnak forming the top line in the NHL and a solid veteran core, the Bruins have themselves a nice blueprint for the future.

Round 2 showed that the Bruins still have a lot of work ahead of them to get over the hump. Acquiring a top-four left-shot defenseman is Sweeney’s top off-season priority. Perhaps the Bruins GM will add a little extra scoring depth on the second or third line.

The good news for Sweeney is he won’t have many hard decisions in terms of signing his upcoming UFA’s. Riley Nash, Rick Nash, Tommy Wingels, Nick Holden and Tim Schaller will likely hit the open market. Anton Khudobin, the other notable UFA, could come back in the backup goalie role with a reasonable price tag.

The Bruins have $65 million committed to 17 players for next season. The salary cap could rise between $78 and $82 million — up from $75 million in 2017-18. With a talented core and a strong youth movement, that extra cap space will be quite the luxury for Sweeney as he enters his fourth off-season since taking over for Peter Chiarelli in 2015.