If there was any doubt who are the two best bantamweight fighters in the UFC before Saturday, there's none left now.

Renan Barao, who defeated Urijah Faber for the interim bantamweight championship in July at UFC 149, scored a solid victory over young hotshot Michael McDonald in the main event of UFC on Fuel TV 7 at London's Wembley Arena.

With a fourth-round submission win, Barao solidified his spot as the top contender to champion Dominick Cruz, who remains sidelined with a knee injury.

"Dominick Cruz, I'm ready for you. Please come quick," Barao said through an interpreter.

The 21-year old McDonald, from Modesto, Calif., was seeking to break Jon Jones' record as youngest titleholder in UFC history. The youngster acquitted himself well, particularly in the first round, where a big right hand to the temple dropped Barao.

But Barao, a teammate of UFC featherweight champion Jose Aldo Jr., regained his composure. And while round one was a tossup, the turned the fight squarely in his favor over rounds two and three, as Barao landed the stronger strikes and shutting down most of the McDonald's attempts to counter.

Barao finally wore McDonald down in round four and set up the winning arm triangle choke. McDonald held out as long as he could, but finally tapped at 3:57 of the round.

"I feel great, it was the result of all the hard work," said Barao. "I left my family, spent Christmas in Rio, spent the whole summer in Rio training very hard. I feel great."

The 25-year old Barao improved to 30-1 (1 no-contest), with his only loss coming in his pro debut. McDonald dropped to 15-2.