Fedors fights give him trouble.

and

Randleman almost won.

Hunt almost won.

Cro Cop did one hell of a fight.

Fujita Rocked him bad.

Coleman had him on his back and pounded on him.

Rogers did the same.

Arlovski had Fedor against the ropes and was winning the round.

All these guys and several more in between all ended up with the same result. A loss on their records. So yes Brock may give Fedor trubble. But trubble is not enough.