Defending champion Andy Murray faces Stanislas Wawrinka on Thursday in the 2013 US Open quarterfinals.  The match is scheduled for 1:30 p.m. ET.  Watch the live stream HERE and HERE.

Murray is three matches away from winning his second straight US Open title.  Murray, a favorite to win the tournament, earned a spot in the quarterfinals on Tuesday by defeating Denis Istomin (6-7, 6-1, 6-4, 6-4).

The next challenge for Murray is much-improved Wawrinka.

Wawrinka, ranked No. 10 in the World, is 40-15 on the season.  He's had a resurgence of sorts, climbing back into the World's top 10 this season for the first time in five years, according to BBC.  One change the 28-year-old Swiss made was the hiring of Swedish coach Magnus Norman.

Since starting work with Norman in April, Wawrinka has noticeably improved.  He won his fourth career title at the Portugal Open.

"I don't know if he's working harder," Murray told BBC.  "He made a coaching change around the clay-court season, which may have helped him because he was without a coach for quite a while.  That could have helped him a bit.

"The match he had with Novak (Djokovic) in Australia at the beginning of the year, that could have contributed to it as well.  There are a lot of things that go into it.  But he hasn't changed any of his strokes technically or anything.  You'd expect most of it to be confidence."

Wawrinka agreed with Murray's assessment.

"It is confidence, for sure.  I had a tough beginning of the year, but in the same time it was really positive for me because I was playing great tennis," Wawrinka told BBC.  "I had some tough losses but I was still working out.

"I think the title in Portugal, beating David Ferrer in the final, helped me a lot with my confidence to pass the next level."

Thursday will be Murray and Wawrinka's 14th career head-to-head.  Murray has won eight of their previous 13 matches, although Wawrinka won their last meeting in two sets at the 2013 Monte-Carlo.

*Stats via ATPWorldTour.com and MatchStat.com.