The only time the Bruins and the Blues played in the Stanley Cup final, it produced one of the most iconic images in the game’s history — Bobby Orr flying through the air after he scored the Cup-winning goal in overtime of Game 4 to win the 1970 NHL championship. That completed the sweep for Boston, which is not too far off in terms of how many are looking at this series, which begins Monday night up in the north end of Beantown.

It’s hard to argue against the fact the Bruins have a better team on paper. They have depth and experience and skill. But it’s harder to argue against the fact the Blues seem to have some inexplicable chemistry since they fired their coach, Mike Yeo, on Nov. 19, and then interim headman Craig Berube helped drag them out of last place in the league, which is where they were on Jan. 3.

So what seems to be a mismatch might actually turn out to be a better series than most expect. It’s not a given that Boston is going to keep reveling in championships. Here’s a look at five key storylines that could predict the winner:

Binnington’s amazing run

The Blues have been propelled by rookie goalie Jordan Binnington, who got his first NHL start on Jan. 7 and went on to pick up 20 wins in his first 25 games in the league. The 25-year-old was named a finalist for the Calder Trophy, and has kept it going in the playoffs, posting a 2.36 goals-against average and .914 save percentage. In the conference final against the Sharks, Binnington allowed only two goals on 77 shots over the final three games to send his team to its first Stanley Cup final since 1970.

If the Blues keep riding this wave, it will be because of Binnington. But if he slips up early, it could be a small crack that ends up sinking their boat.

Bruins layoff

The Bruins will have had 11 days off between sweeping the Hurricanes in the conference final and playing Game 1 against the Blues. That is one more day than that Islanders had between the first and the second rounds, and their rustiness was certainly a factor in them getting swept by Carolina.

The break does give the Bruins some time to get a healthy, as Zdeno Chara missed Game 4 of the East finals with an ankle injury and Brad Marchand suffered a little nick to his left hand during an open intrasquad scrimmage Thursday — which happened to draw 16,000 fans at TD Garden. There was also a bit of a sickness going around the locker room this week, but it seems like they should be at full power come Monday night.

Blues’ physicality

Bruins head coach Bruce Cassidy said the Blues are “probably the most physical [team] that we’ve seen,” and with Boston’s own burly mentality, it should be a slugfest. Although Chara is the biggest player on the ice at 6-foot-9, the Blues are a bigger group overall, and they like to throw their bodies around. Yet they do it in a controlled manner, rarely letting emotions get the best of them. If they can hit the Bruins and get them to counter in anger — here’s to looking at you, Marchand — then they could get under their skin.

Rask’s revenge

As good as Binnington has been, Bruins goalie Tuukka Rask has been better this postseason, putting up a 1.84 goals-against average and .942 save percentage. If the postseason ended now, it would be the fourth-best save percentage in playoff history (with a minimum of 15 games started). Surely Rask remembers the most recent time he was in the Stanley Cup final, suffering a loss to the Blackhawks in 2013. He seems determined to get the club’s first Cup since 2011.

Red-hot power play

Unlike Boston’s 2011 team that had the worst power play for a team that won — scoring on just 11.4% of its chances — this year’s team might be the best, coming in scoring at a clip of 34%. The Blues have a terrific penalty kill, but this will be their most formidable task.

Prediction

The ride is over. The better team wins. Everyone has to deal with one more insufferable Boston championship. Bruins in six.