He fights pretty evenly with Mileena, until she administers a Groin Attack and impales him against a tree. Mileena completely forgets about him and starts fighting with Kitana. She's about to kill Kitana, when Johnny pulls a Big Damn Heroes by stabbing Mileena in the foot, leaving her wide open for a fatality.
In the Season 2 Finale, Johnny is able to briefly hold his own against Liu Kang, despite being stabbed, having an arm in a sling, and other injuries. Even his opponent admits he's good.
Liu Kang: You've gotta be kidding me. You were that actor, right?
Johnny: (Clutching his injured arm) Still am.
Liu Kang: Heh. Always thought you had a stunt double.
Johnny: Nope. All me.
Liu Kang: ...Obviously. Must have skills to be invited here.
Liu Kang: Would you like to have a quick death in the dirt or a chance on your feet? (Johnny answers by standing tall and assuming a fighting stance despite his injuries, and then holding his own for a few seconds.) You're good.
Speaking of the above spoilered character, he's been handing out brutal beatings in all his fight scenes. He started the fight with Johnny Cage by throwing out an attack that knocked out Striker despite missing, and all he had between fighting Cage and Striker was a heaping helping of stun gun. Kung Lao arrived in time to stop him from finishing Striker, but the odds still don't look good for the heroes. After all, they're up against Liu Kang, the previous champion of Mortal Kombat.
Kenshi versus Ermac. Short but Awesome.
On a more meta level, having Cary-Hiroyuki Tagawa reprise his movie role as Shang Tsung.
And Tsung proceeds to convert Liu Kang to Outworld. It takes a special sort of evil awesome for a villain to make a former rival their right hand.