Genie Bouchard Cheers On New Beau Mason Rudolph At Steelers Game

Genie Bouchard and Mason Rudolph could be getting serious ... the tennis star showed up to the Steelers game Sunday with friends to cheer on her new beau!!!

We broke the story ... Genie and the Steelers backup QB kicked off a romantic fling recently -- and clearly, the fire is still burning hot.

'Cause just weeks after 26-year-old Genie was spotted out and about near Rudolph's Pittsburgh-area home ... she headed to 25-year-old Mason's game against the Titans in Tennessee.

And, while Mason didn't play in the win (he's backing up a healthy Ben Roethlisberger this season) ... didn't seem Genie minded too much -- check out her smile!!!

Yeah, looks smitten to us!!

Neither Genie nor Mason has gone public with the relationship yet ... but posting pics from games means we could be getting close to IG offish any day now.