Originally published on ProWrestlingSheet.

A ghost from Brock Lesnar's past came back to haunt him before he could celebrate winning the WWE Championship on SmackDown earlier tonight.

Lesnar made short work of Kofi Kingston to capture the gold in the main event of the debut episode of Friday Night SmackDown on Fox, but his smiles were short lived. Before The Beast could begin his celebrations, Rey Mysterio made his way to ring ... alongside UFC fighter Cain Velasquez.

Lesnar and Velasquez scuffled before Brock squirmed out of the ring. The pair continued to stared each other down until the show went off the air.

In case you're not aware, the last time these two men came to blows was in UFC back in 2010. Velasquez won that battle easily, so Brock will most certainly be looking for some payback.

As we previously reported, Velasquez had been in talks with WWE, but was also interested in AEW.

Check out footage Velasquez's WWE debut below.