The Toronto Maple Leafs' improbable third period comeback and eventual overtime win in Game 4 of their first-round playoff series against the Tampa Bay Lightning Monday seemed so unlikely not even fans knew how to react. 

Trailing 4-1 in the third period, the Maple Leafs scored three goals, including two by center Auston Matthews, in just over six minutes to tie the game and force overtime. 

Alexander Kerfoot scored on the power play at 4:14 of overtime to give Toronto a 3-1 series lead, but no one was more surprised by this feat than the Maple Leafs’ fans, who are just a win way from seeing their team claim their first playoff series win since 2004. 

MAPLE LEAFS PULL OFF STUNNING GAME 4 COMEBACK; ALEXANDER KERFOOT POTS OVERTIME WINNER

Several videos posted to social media appeared to show fans struggling to contain their excitement and, no doubt, shock. 

One man was seen shouting the good news over a cell phone while another couple — one a Maple Leafs fan, the other a Lightning fan — seemed to have an animated conversation about the game. 

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The phrase "It was 4-1" soon caught fire on Twitter. 

Toronto has been eliminated from the first round each of the past six postseasons, including a year ago when Tampa Bay rallied from 2-1 and 3-2 deficits to advance in seven games.

By comparison, the Lightning have won 11 of 12 playoff series over the past three postseasons, advancing to the Stanley Cup Final three straight years and winning the championship twice.

Game 5 is set for Thursday night. 

The Associated Press contributed to this report.