Lightning's Mikhail Sergachev's Smokin' Hot GF In Tears Over Cup Win, 'My Champion'

Tampa Bay Lightning star Mikhail Sergachev is clearly winning both on AND off the ice ... check out how his GF reacted to his Stanley Cup victory Monday -- she was crying tears of joy!!

Elizaveta Fedotova -- a smokin' hot yoga instructor -- posted footage of her watching her BF win his first-ever NHL championship ... and it's pretty touching.

Fedotova was catching the game on a small laptop ... and when the Lightning sealed the 2-0 victory to give them the series win over the Dallas Stars -- she started bawling!!!

"Simply the best morning this year!" she said in a caption after the win on a photo of a celebrating Sergachev. "My love! My champion."

Fedotova also posted a picture of her FaceTiming with the Lightning defenseman right on the ice after the win ... and it's adorable.

The two have been dating for years ... and they seem to have an amazing relationship -- Sergachev has even posted about how he takes yoga classes with her.

Great time for the 22-year-old, huh?!