Eli Manning: I Can Explain My Super Bowl Face ...

What the hell was up with Eli Manning's face???

It's the question everyone was asking when the camera cut to Eli last night moments after Peyton's Broncos scored their final touchdown to secure a Super Bowl victory

Now, Peyton's younger bro is finally breaking his silence ... telling us what was going through his mind -- and why he wasn't jumping for joy like everyone else in the VIP suite!

By the way, Eli's face has also become a pretty popular meme on social media -- and the good news ... Eli approves -- saying it's all in good fun.