The sporting world is still getting used to the realities of hosting major sporting events without fans - as one commentator at the US Open found out the hard way.
The Flushing Meadows tournament is being played with nobody in the stands due to the ongoing effects of the coronavirus pandemic, as the first major to be held since the outbreak of the virus.
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Despite some controversy after Frenchman Benoit Paire tested positive for the virus, the tournament has largely proceeded as planned.
The impact of the lack of fans was acutely felt by Alexander Zverev though who, during a tense moment in his eventual four-set victory over Borna Coric.
Zverev dropped the first set to Coric, but bounced back to tie the game after winning the second set.
He was still edgy while serving in the third set though, pausing to tell ESPN commentator Brad Gilbert to be quiet.
“You’re talking too loud, man,” Zverev said.
“I can hear every single word you’re saying.”
Gilbert, who had been discussing Zverev’s nine double faults to that point in the match, sheepishly apologised.
It’s been a strange tournament for Zverev, whose second-round match was delayed after New York State health officials questioned whether his opponent had been in close contact with the COVID-19 positive Paire.
Alexander Zverev cruising at US Open
he second time in as many majors this year with his four-set win over Borna Coric in the US Open quarter-finals.
The fifth-seeded Zverev got off to a slow start but raised his game to advance 1-6 7-6 (7-5) 7-6 (7-1) 6-3 despite 12 double faults and 46 unforced errors.
Coric made a flying start and needed only 24 minutes to wrap up the first set during which he took advantage of a flat Zverev.
However, Zerev showed plenty of fight in the second set as he came back from a break down and 4-2 to level the match by winning the tiebreak before unleashing an extended roar.
After trading early breaks in the third set, Zverev cruised through another tiebreak while a single break in the fourth set proved decisive.
"I just started playing maybe a little bit more aggressive because if I would've played the way I played (at the start), it's not the level for a quarter-final match at a grand slam," Zverev said.
The German's next opponent will be the winner of Tuesday night's last-eight clash between 12th-seeded Canadian Denis Shapovalov and Spanish 20th seed Pablo Carreno Busta.
Zverev, who reached a major semi for the first time at the Australian Open in January before losing to Dominic Thiem, is the first German to reach the semi-finals of the men's singles at the US Open since Boris Becker in 1995.
"It's great to be in the semi-finals and unfortunately we haven't been there in 25 years for a German player, but there will be many more after me and hopefully I can continue the way I'm going," Zverev said.