The Islanders fell 4-3 to the Canadiens in Roy's return.

MONTREAL -- The New York Islanders came back down by two in the third, but allowed the go-ahead goal late and fell 4-3. 

Here's how it happened:

The Islanders were a mess from the opening puck drop, as they were just completely out of sync.

After Hudson Fasching turned the puck over, he recovered before chipping the puck out of play, earning himself a delay-of-game penalty at 6:18 of the first.

On the man advantage, tic-tac-toe passing allowed for Nick Suzuki to tap one home from the form of Varlamov at 7:06 of the first to make it 1-0 Montreal.

With a chance to go up the ice, Pierre Engvall went south with the puck before sending it across the Islanders' zone to Sebastian Aho.

But Aho failed to corral the pass, and Cole Caufield collected the loose rubber and deked around Samuel Bolduc and Varlamov to make it 2-0 Canadiens at 11:36 of the first.

While on the power play, allowing a 3-on-2 and a 2-on-1, a Kyle Palmieri holding penalty ended that, leading to 4-on-4 hockey.

That's when Mike Matheson carried the puck along the right boards before finding Sean Monahan for a tap-in front, fooling the Islanders as if he was going to go behind the net.  

The Islanders went into the first down 3-0, with seven giveaways. 

Hudson Fasching left the game at 8:42 of the second after falling hard into the end boards following a breakaway chance. 

The Islanders recorded seven power-play shots in the middle frame but failed to score. David Savared robbed Horvat of a wide-open cage in the final five minutes of the second, getting his stick and skate with a wide-open cage. 

New York outshot the Canadiens 19-7 in the second. 

The Islanders found themselves on a five-minute power play after Brendan Gallagher got ejected after elbowing Adam Pelech in the head, with No. 3 leaving the game at 11:52 of the third.

With 2:01 remaining on the power play, Barzal sniped Montembeault to make it a 3-2 game at 14:52 of the third. Dobson and Palmieri earned the assists.

Then at 14:52 of the third, Kyle Palmieri buried one after a few wacks to tie the game at 3-3. Dobson and Horvat were credited with the assists. 

But at 17:50, the Islanders turned the puck over, and Monahan scored his second of the game as his one-timer from the high slot beat Varlamov's high glove side to give Montreal a 4-3 lead. 

UP NEXT: The Islanders host the Florida Panthers on Saturday night at 7:30 PM 

LINES: 

Anders Lee -- Bo Horvat -- Mathew Barzal

Hudson Fasching -- Brock Nelson -- Kyle Palmieri

Simon Holmstrom -- Jean-Gabriel Pageau -- Julien Gauthier

Hudson Fasching -- Casey Cizikas -- Cal Clutterbuck

Alexander Romanov -- Noah Dobson

Adam Pelech -- Sebastian Aho

Samuel Bolduc -- Scott Mayfield

Semyon Varlamov

Ilya Sorokin