Tiafoe won the first set 6-3.

The 26-year0ol dhas shifted from playing on the defensive to dominating as the match goes on.

The American has pulled Dimitrov from one corner to the next, moving up to the net, and put away irretrievable shots.

His Bulgarian counterpart, however, has an impressive serving record. He leads the league in the number of first serve points won. While his overall average is 85% of first serves won, this game he has won 67%.

He broke Dimitrov, now leading 3-2 in the first set.

The 26-year-old has been playing offensively, often coming up to the net. In some cases, Dimitrov has predicted that Tiafoe was approaching, offering him a lob, but in others, Dimitrov has been forced to make risky shots down the line.

Both men have won on their serves. The rallies haven’t been long, typically ending with one of them making an unforced error within the first few shots as they still seem to be warming up.

So far, Dimitrov appears to be one step ahead of the young American. He has been accurately anticipating when he will move in and where he will try to land a drop shot.

In a highlight moment, Tiafoe recovered from a wide shot to his backhand with lob. Dimitrov returned with an overhead slam to the American’s forehand for a winner.

Dimitrov is up two games to one in the first set.

Dimitrov started off strong. He opened with an ace on the first point. And another ace on the second.

The 33-year-old Bulgarian largely had Tiafoe on the defensive, taking the first game with a killer shot that hit the outside of the right singles line.

The 26-year-old American is serving next…

Frances Tiafoe and Grigor Dimitrov are about to face off at Arthur Ashe Stadium.

The player who wins will face American Taylor Fritz, the number 12 seed, in the semis.

Sabalenka defeated Zheng 6-1, 6-1.

“She is playing such incredible tennis and it was tough facing her,” the Belarusian star said after her victory about Zheng.

She is heading for the semifinals where she will face American player Emma Navarro.

When asked what to do to get New Yorkers to support her in the semis, she joked: “Drinks on me!”

Sabalenka has been dominating from the baseline, hitting with a power that has gone unreciprocated by Zheng.

The number 7 seed, meanwhile, has not only been forced to play defense, being pulled from one side of the court to the other, but also has struggled with her first serve.

The Belarusian player is now ahead by one set and currently up by 4 games to 1 in the second.

On that particular occasion, Gauff’s forehand struggled, but her serve completely let her down. She served 19 double faults, and 11 in the final set to cap off a difficult summer, where she has lost in the last 16 of the last three major tournaments.

Since the defeat, there have been calls for Gauff to replace her coach Brad Gilbert and look elsewhere – and there has been an unlikely offer from Nick Kyrgios.