Gael Monfils d. Lucas Pouille 6-4, 6-3, 6-3 

Gael Monfils is into a Grand Slam semi-final without dropping a set. It’s a sentence that, for so long, we didn’t envision writing. But then again, Gael Monfils isn’t the same player he once was. 

Since turning professional 12 years ago, his tennis has been magical and maddening, often in the same match, sometimes in the same point. But since the turn of the year, he has produced the level of steady play his career craved. So here he is, into the final four at the US Open for the first time with a comfortable victory over compatriot Lucas Pouille, who is enjoying a breakthrough year. The flair is still there, the showman is always lurking. After serving out the first set with ease he opened the second set on his own serve by attempting an audacious through-the-legs shot. It wasn’t necessary, but it’s what came next that was most impressive: a hold and a break to send him on his way once more.

More focused, more controlled, more disciplined, but is Monfils still having fun? “Always. You know, always. No matter what, it looks maybe a bit more serious, like everyone mentions this year, but I play tennis because I have fun. I play tennis because I love the sport.”

Next up: Novak Djokovic. And, well, he’s won 53 of his last 54 matches against Frenchmen.

Verdict: Never has consistency been more welcome in tennis. Monfils has reached the quarter-final or better at nine events this year and with a maiden major two victories away, it’s hard not to wonder about what might be about to happen to one of the game’s most talented players. Standing in his way though is Novak Djokovic and then possibly Andy Murray. It’s a big ask, and then there’s this stat: he’s 6-19 in title matches.

For Lucas Pouille, he backs up his first major quarter-final at Wimbledon with another last-eight performance at Flushing Meadows. At just 22, he’s on the right track.

Angelique Kerber d. Roberta Vinci 7-5, 6-0 

It’s five matches played and just two completed for Novak Djokovic. After benefitting from a Jiri Vesely walkover in the second round and a first-set retirement from Mikhail Youzhny in the third, he was walking off court early once more on Tuesday as Tsonga picked up a knee injury before withdrawing. In the two sets completed, Djokovic played some wonderful blanket defence, scrambling down balls in typical style and returning them with interest.

“As the tournament progresses, I feel like I'm getting better,” he said. “Of course this Grand Slam is very unique for me. I never experienced something like this to have three retirements on the road to the semifinals. I can only wish all of my opponents a speedy recovery.”

We have come to expect deep runs from Djokovic at the Slams, but it still doesn’t make the numbers any less impressive. He has now won 23 of his last 24 Grand Slam quarter-finals.

Verdict: It’s hard to say really. Will Djokovic struggle from his lack of playing time? Will it work in his favour? Will his pre-tournament injuries hold up in a five-set battle? There are a lot of unknowns. One thing we do know though, after his blip at Wimbledon the world No.1 is back in the business end of a Slam and he’s a frightening proposition for anyone.

Caroline Wozniacki d. Anastasija Sevastova 6-0 6-2

It all ended in tears for Anastasija Sevastova. The Latvian’s fairytale return to the big stage turned into something of a nightmare in the second game of the opening night match on Arthur Ashe when she rolled her ankle. Her movement was limited and Caroline Wozniacki was understandably ruthless, running her from side to side, using every inch of the court. Sevastova fought on valiantly, but there was little she could do. Wozniacki is back in the US Open semi-final for the fifth time.

Verdict: This run of results could not have come at a better time for Caroline Wozniacki, who has plummeted down the rankings in recent months. At a lowly world No.74 she becomes just the sixth player ranked outside the Top 50 to advance to the semi-finals in New York. She feels comfortable here and her consistent game will ask questions of Kerber in the semi-final. The German will need to come out and win because Wozniacki won’t give it to her.