An emotional Nick Kyrgios of Australia upset 21st seed Russian Mikhail Youzhny in the opening day of the U.S. Open on Monday.

Kyrgios. who defeated defending champion Rafael Nadal in the fourth round of  the All England Club en route to his first ever quarterfinals appearance in a major tournament, pulled off another upset defeating Youzhny, 7-5, 7(7)-6(4), 2-6, 7(7)-6(1) in an exhausting three-hour match.

Like Us on Facebook

The 19-year-old Kyrgios cranked in 26 service aces and 68 winners but was nearly disqualified after committing three code violations.

Out of frustration, Kyrgios smashed a ball out of the stadium in the second set and then in the fourth set, he shouted out the F-word and was penalized with a game to fall behind Youzhny 3-1.

But the teen was unfazed as he held his next service game and went on to break the Russian to finally send him to the next round.

The 32-year-old Youzhny defended the young Kyrgios after the match saying that "it's normal" to have such outbreaks for Kyrgios is young and have full of emotions.

"He looks like he has lots of emotions. Sometimes it helps, sometimes it's not," said Youzhny.

Kyrgios admitted of his emotional outbreaks and says that he is trying to eliminate them or at least tone them down a bit.

"It's a work in progress. It's something that's always been there," Kyrgios said. "Maybe I will be able to manage it in the future."

Kyrgios will face Italian Andreas Seppis in the second-round.

In other matches, Rogers Cup champion Jo-Wilfried Tsonga and Andy Murray advanced to the second round after defeating their respective opponents in four sets, while third-seed Stan Wawrinka and Tommy Robredo cruised through their matches to go on to the next round.

TagsNick Kyrgios, Mikhail Youzhny, rafael nadal, Jo-Wilfried Tsonga, andy murray, Stan Wawrinka, Tommy Robredo