Winston-Salem Open 2017: Steve Johnson, Hyeon Chung Fall on Thursday

The entire Winston-Salem Open has featured plenty of surprises throughout the week, and Thursday's action was no different.

Only four seeded players reached the quarterfinals, featuring just two in the top eight. Things didn't go according to plan in the latest round either with more favorites struggling to advance.

Every player is trying to leave on a high note in the final tune-up before the U.S. Open, and it has led to a competitive draw. Here is a look at the latest action from North Carolina.

Schedule/Results

Kyle Edmund def. No. 6 Steve Johnson; 5-7, 6-3, 6-3

Damir Dzumhur def. No. 13 Hyeon Chung; 6-4, 6-2

No. 1 Roberto Bautista Agut def. Taylor Fritz; 6-2, 7-6(3)

Jan-Lennard Struff def. No. 14 Borna Coric; 6-4, 7-6(2)

Full draw available at ATPWorldTour.com.

Recap

Steve Johnson Goes Down

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There were just two seeded players from the United States competing in front of the home crowd this tournament, and No. 3 John Isner only lasted to the round of 16. He lost to Borna Coric in his second match in Winston-Salem.

This left Steve Johnson, who kicked off his tournament with two straight-set wins before failing to close out against Kyle Edmund on Thursday.

Johnson dominated with his serve early, 10 of his 14 aces on the day coming in the first set. He never faced break point while winning 7-5. Unfortunately, his sloppy play cost him as the match progressed.

The American finished with nine double-faults and only got 47 percent of his first serves in play.

Edmund took advantage with solid defense and consistency on his serve, coming back from a set down to earn a spot in the semifinals.

Damir Dzumhur Keeps Up Hot Streak

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In four matches this tournament, Damir Dzumhur has four wins and just one lost set despite facing some serious competition. After knocking out Denis Istomin, Gilles Simon and Horacio Zeballos in the first three rounds, he kept it up with an easy win over Hyeon Chung.

The Bosnia and Herzegovina national was solid serving the ball, as evident with this match-winning ace:

Of course, he really separated himself by attacking Chung's second serve. The No. 13 seed won just 15 of his 31 points on second serve, saving just four of his eight break points.

After reaching the semifinals of his last ATP Tour event in Mexico, Dzumhur remains hot and a serious threat to bring home his first career title.

He will try to continue his run with a semifinal matchup against Edmund Friday. 

Bautista Agut Holds Steady 

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No. 1 seed Roberto Bautista Agut ripped off his third consecutive straight-set win at the Winston-Salem Open as he downed American Taylor Fritz 6-2, 7-6(3) by winning a whopping 85 percent of his first-serve points Thursday night. 

The Spaniard also emerged victorious on 73 percent of his second-serve points while Fritz managed to convert 48 percent of his second-serve points into wins. 

By virtue of the win, Bautista Agut has now clinched a spot in the semifinals and has a clear path to his second singles title of the season. 

That's welcome news for the 29-year-old, whose U.S. Open tune-up slate started off on a sour note when he was bounced from the Western & Southern Open in the first round by Jared Donaldson. 

Struff Knocks off Coric 

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Jan-Lennard Struff is through to the semifinals after downing Borna Coric 6-4, 7-6(2) in a match that lasted just under 90 minutes. 

Needless to say, that result was surprising. 

Prior to Thursday night, Struff hadn't qualified for a semifinal all year and had been dispatched from his last nine tournaments in either the first or second round. 

However, the German's luck changed in a big way against Coric as he recorded 10 aces and dropped a meager three first-serve points. 

Struff will now turn his attention to Friday's showdown with Agut. 

Those two met earlier this year in Barcelona, when Agut sent the 27-year-old packing 6-1, 6-3 on clay. 

Friday Schedule

Kyle Edmund vs. Damir Dzumhur (7 p.m. ET)

No. 1 Roberto Bautista Agu vs. Jan-Lennard Struff (9 p.m. ET)