TORONTO (AP) — If Jurgen Klinsmann is pushing Michael Bradley to play better, the Toronto FC midfielder doesn't mind.

The U.S. coach this week repeated his opinion that Bradley and Clint Dempsey accepted a less challenging level of opposition when they returned to Major League Soccer from European clubs. That sparked an angry response from MLS Commissioner Don Garber, who said Klinsmann should not criticize the league and defended its quality.

"I've certainly had moments in my career where people have challenged me, said that I've not been good enough, said that I'll never be good enough. But not only has that never stopped me, it continues to motivate me and fuel me even more," Bradley said after practice Friday.

Bradley left Roma in January to sign with MLS. Dempsey, the U.S. captain, departed Tottenham in August 2013 for the Seattle Sounders.

Klinsmann said Monday that Bradley "has to prove that he hasn't lost a bit."

"And so for me, it's all very simple," Bradley said. "My record when I've played for the national team and my commitment and contribution is there for anybody to look at and take from it what they want."

Bradley, 27, has made 91 appearances for the U.S. and was a key player at the 2010 and 2014 World Cups.

"I sleep very easy at night knowing everything that I have given and everything that I've put into it," he said of the national team. "And I'll continue to do so until they don't let me anymore."

Toronto FC coach Greg Vanney, a former U.S. national team player, called Klinsmann's view of MLS "harsh."

"I think this league is extremely challenging, but maybe in different ways," Vanney said. "Michael shows up every day and he puts in the work," Vanney said. "And he's an honest worker. So I think if you're the type of person who comes back to this league and you're on vacation, I think it can hurt you. If you're the type of person like Michael and what I hear of the other guys that come back, this league, it just provides you with a different challenge, that's all. I think it can keep you sharp and it can keep you ready for any international play."