Travis Kelce and Patrick Mahomes kept the party going Saturday night in Vegas, hitting up XS nightclub with their team as they belted out Queen's "We Are the Champions."

The group partied their faces off with the help of EDM star Marshmello. Travis is up on stage as he and some other guys sprayed the crowd with champagne as everyone went nuts.

It was pretty intense ... Travis was covered in sweat, at times wiping his head with a towel.

Of course, Marshmello played "Love Story" as an homage to Travis's relationship with Taylor Swift, and Trav knew the drill ... jumping and singing along.

But the real moment was when Travis, Patrick and co. belted out "We Are The Champions," as everyone in the joint just lost it.

Earlier in the day, Travis and Patrick, along with other teammates, hit up LAVO at the Bellagio for a brunch party ... and party they did!

Travis is really racking up the miles, returning from Sydney where he went to the zoo with his GF and then hit up her show.

What's so remarkable ... the Aussies aren't into American football, but Travis walked in like a superstar and the crowd went wild for him.