Tennis legend Andre Agassi revealed that he learned how to beat a rival by watching his tongue on serves

• Tennis legend Andre Agassi learned to beat Boris Becker by watching his tongue.
• Agassi realized Becker would move his tongue in the direction of his serve.
• After going 10-4 vs. Becker all-time, Agassi eventually floored Becker by revealing his trick.

Legendary American tennis player Andre Agassi lost his first three matches against Boris Becker. Then he realized Becker was tipping his serves with a small tick.

In a 2017 interview with The Players Tribune's Unscriptd, Agassi said that he used to struggle mightily to return Becker's serve. Then, after some film study, he realized Becker would indicate how he was going to serve by moving his tongue.

"I started to realize he had this weird tick with his tongue," Agassi said. "I'm not kidding. He would go into his rocking motion, his same routine, and just as he was about to toss the ball, he would stick his tongue out. And it would either be right in the middle of his lip, or it'd be to the left corner of his lip.

"If he's serving in the deuce court and he put his tongue in the middle of his lip, he was either serving up the middle or to the body. But if he put it to the side, he was going to serve out wide."

Learning the tick helped Agassi return Becker's serves, but he had another challenge: not letting Becker know that he could guess his serves.

"The hardest part wasn't returning his serve - it was not letting him know that I knew this," Agassi said. "I had to resist the temptation of reading his serve for the majority of the match and choose the moment when I was gonna use that information on a given point to execute a shot that would allow me to break the match open."

After losing to Becker in their first three matches, Agassi then won eight straight over Becker, including some high-profile wins like the 1990 U.S. Open and French Open semifinals. He finished 10-4 all-time against Becker, though Becker's fourth win came in the 1995 Wimbledon final.

Agassi said he later revealed the tick to Becker over a beer at Oktoberfest - and Becker was astonished because he had been perplexed by how Agassi could read him.

"We went out and had a pint of beer together, and I couldn't help but say, 'By the way, did you know you used to do this and give away your serve?'

"He about fell off the chair. He said, 'I used to go home all the time and just tell my wife, it's like he reads my mind.'

"He said, 'Little did I know, you were just reading my tongue.'"

Watch the video below: