LHe was struggling against a 45 year old Randy...
It's easy to find the fight online. I would suggest you do so.
Randy's offense consisted of leaning on Lesnar for the opening minute. Then getting taken down, fighting back up, and getting taken down again. He lands a "take down" at just about 2:22 on Lesnar and it's simply semantics... it's pointless. I'm almost shocked they counted this, as Lesnar is on his knees at the start of it. Regardless, Lesnar instantly reverses it. Couture then spends the end of the round clinching more. He landed 6 sig strikes in the opening round.
Next round the two exchange a couple times very early on. On the third exchange Randy's chin is clipped by an inside elbow, and he stanky legs backwards in retreat. It's just 15 seconds into the round. Brock rushes in and gets clinched. To his credit, Randy throws a wonderful knee to Brock's face here, and it's the best thing so far for Couture. They jockey for 30 secs and eventually Brock returns the knee on the break. Randy is at best negating a bit of Lesnar's offense, but he's not winning by any measure. He was threatened heavily on the mat in round 1, and here in round 2 he's done almost nothing except survive a big shot.
About 3:45 left and the two again start to exchange. Randy manages to open a cut and Brock keeps moving in. They trade again and Randy eats a tight short uppercut and backs away... To his credit, Randy stuffs a short take down attempt and clinches again. Randy does a good job at making Lesnar blow through his gas tank but is doing no damage. At all. Brock shoves off and lands another solid knee to Randy's face. Oof. There's just over 2 minutes left and the two exchange and Randy goes down. Roughly 29 hammer fists later the ref calls it.
I would not call this struggling. He won the striking exchanges, and did more damage on the clinch breaks, and controlled the ground scramble.
