Goodbye, Milos Raonic. Too bad the U.S. Open didn't get to see you at your best.
Canada's star and the fifth seed at Flushing Meadows, Raonic succumbed to cramping and was not able to save himself against Ryan Harrison, an unseeded American.
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Will Steve Johnson join the list of upset victims? That's possible, given his Thursday match is against Juan del Potro. Stan Warwrinka also plays on Thursday, in a second-round match expected to begin about 5:30 p.m. ET.
Andy Murray, seeded second, has an early match against Spain's Marcel Granollers. Expect that to begin about 1 p.m. ET.
Weather could be a factor. Showers were expected early, possibly delaying the start of Thursday's schedule. Afternoon rain also was in the forecast.
Harrison, ranked No. 120 in the world, has long been fodder for the world's best players. This time, he took advantage of Raonic's struggles.
"It was probably just nerves and stress, a mental sort of over-exuberance," Raonic told media members after the match. "Cramping in the left arm, right forearm there towards the end of the third set, both quads, a little bit in the hip flexor on the left. It was just catching me all over.
"I couldn't switch grips from one point to the next. There were a few points where I would hold the racquet with my left hand and trying to stretch out my right hand in between shots."
Raonic said he was “my own worst enemy today. “I tried the best I could to find my way out of it. My body didn’t let me.”
Take nothing away from Harrison. He deserved his three-set victory.
Johnson has a challenge against del Potro. After numerous wrist surgeries, de Potro had to rebuild his game. He seems in peak form, having beaten Novak Djokovic and Rafael Nadal in the Rio Olympics, where he won the silver medal.
Can another American pull off a second-round upset? In action are Jared Donaldson, all of 19 years old; and journeyman Donald Young, who faces the booming serve of Ivo Karlovic.
Here is the schedule of men's matches at the U.S. Open.