Alex de Minaur calls out chair umpire as fans blast illogical rule in US Open clash against Jordan Thompson

Alex de Minaur vented his frustration with the chair umpire after Aussie rival Jordan Thompson's hat fell off during play at the US Open to prevent him from winning the point in a bizarre tennis rule. De Minaur and Thompson engaged in a tight fourth round clash at the US Open with an Australian guaranteed to reach the quarter-final at Flushing Meadows.

De Minaur stormed out of the gates and left his fellow Aussie rival shell-shocked in the first set with a 6-0 drubbing. However, Thompson showed grit and determination to fight his way back into the match to take the second set 6-3. Although there was a controversial moment in the second set at 30-30 on Thompson's serve.

De Minuar had moved Thompson around the court and forced him to throw up a high recovery shot on the run. The No.10 seed went to put the smash away to earn two break points, but Thompson stopped and gestured to grab the attention of the the chair umpire.

Thompson's hat had fallen off during the play as he put up the towering recovery shot. The chair umpire hadn't seen the hat fall off and followed the action as de Minaur won the point. Unfortunately for de Minaur, Thompson used a controversial tennis rule to his advantage having stopped during play. This was within his right.

Once an opponent's hat falls off during play the point needs to be replayed. If Thompson's hat falls off a second time then he can face a point deduction. But since it was the first time during the match, Thompson told the chair umpire he stopped because the point needed to be replayed.

De Minaur approached the chair umpire and questioned why the point hadn't been stopped as soon as Thompson's bright yellow hat had fallen off. De Minaur was the clear favourite to win the point since he was granted a smash at the net, even though the smash went back at Thompson who returned it. De Minaur then hit a winner.

The chair umpire explained she was following the ball and had missed the hat falling off during the point. The No.10 seed accepted the decision and the chair umpire's reason and replayed the point against his fellow Aussie. Thompson used the break to his advantage and managed to go on and hold the game. He then capitalised with the momentum to level the match at one-set all.

De Minaur didn't show his frustration and managed to brush if off heading into the third set. However, fans questioned the bizarre rule and why de Minuar wasn't automatically awarded the point for his opponent's hat falling off.

Alex de Minaur confused over tennis rule

After the match, de Minaur explained his confusion during the post-match press conference. He admitted he felt the chair umpire made the right call at the time. “That’s happened to me so many times. (But) I’m normally the one with my hat just falling off,” he said.

“The only thing that I felt (was) puzzling is that I wasn’t sure, and I actually in the moment didn’t ask the ref, but I was curious if I would have hit a winner on the next shot, if it still would have been a replay or not.

“Because I’ve had times where my hat has fallen off (and) I’ve stopped, but the opponent hasn’t, and the referee deems it as it’s only endangering me and not my opponent (and that) therefore, it’s not a replay of the point.

“It feels like the rule just changes, depending on the ref, if I’m honest. I wouldn’t be able to tell you the actual rule book, because I have had so many different situations where they have played it off different ways, but in my eyes, I feel like any time the hat falls off, it should be a replay point, no matter what.”

Thompson put up a very strong fight against his younger rival and made de Minaur work for every point in typical Aussie style. De Minaur improved his serving performance in the third and fourth set to pull away to win 6-0, 3-6, 6-3, 7-5.

De Minaur showed his respect for his friend and fellow Aussie during his on-court interview having praised Thompson for his mentorship throughout the years. "Yeah look, I have so much respect for Thompson. We grew up together. He has been like a big brother for me," de Minaur said after the match.

When asked about how he was approaching the US Open, the No.10 seed pinpointed his determination as the key. "Just the mentality....try to play every point and win every point. Just compete my heart out. Thanks for those who stayed," de Minaur added to a huge roar from the crowd.

Alex de Minaur matches Lleyton Hewitt feat at US Open

De Minaur's win saw him emulate Aussie tennis icon and his mentor Lleyton Hewitt. The 25-year-old became the first male Aussie to reach the quarter-final in three consecutive grand slams since Lleyton Hewitt 20 years ago. Incredibly not even Ash Barty or Sam Stosur achieved this feat at the height of their careers.

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He will next play Jack Draper in the quarter-final with a huge opportunity to reach his maiden US Open semi-final. De Minaur will now be looking to once again emulate his Davis Cup captain's 2004 run and lift the trophy. Most importantly for de Minaur, the Aussie was moving with speed and agility having appeared to recovered from the hip injury that saw him retire from Wimbledon and withdraw from the Paris Olympics singles competition.