Lleyton Hewitt caught in rule breach as Alex de Minaur's tactical failure laid bare

Lleyton Hewitt appeared to flout the rules around coaching during Alex de Minaur's loss at the Australian Open on Sunday night in a desperate attempt to get a key message to his player. De Minaur appeared to be heading towards a first career quarter-final berth at Melbourne Park, before Rublev produced a stunning turnaround to blitz the Aussie in the final two sets.

World No.10 de Minaur was up two-sets-to-one over Rublev, but was blown off the court in the fourth and fifth sets as the Russian pulled off a bold tactical switch. Rather than engage in long rallies with the speedy de Minaur, the World No.5 used his big forehand and went for winner after winner to shorten points.

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In staggering scenes, Rublev fired off a number of winners as he won the last two sets 6-3 6-0 against a hapless de Minaur. But there appeared to be one final glimmer of hope for the Aussie when Rublev started limping at 4-0.

It looked as though the Russian was struggling with a calf issue and stopped running for a number of balls that he'd normally get. He continued to fire away with his forehand as commentators suggested de Minaur needed to make his opponent move more.

And that's exactly what Hewitt was thinking as well. Channel 9 cameras spotted the moment Hewitt tried desperately to relay that message to de Minaur, but he wasn't allowed to under the rules.

Why Lleyton Hewitt's actions aren't actually allowed

While mid-match coaching is allowed nowadays, it can only be done when the coaches are at the same end as the player. Coaches are not permitted to speak to the player when they're down the other end, which is what occurred with Hewitt and his mentee de Minaur.

Sitting next to de Minaur's coach Adolfo Gutierrez, Hewitt gestured with his hands for de Minaur to start making Rublev run. He stopped himself when he noticed that he was on the big screen in Rod Laver Arena, but the coaches box cam picked up Hewitt getting de Minaur's attention to deliver the message just seconds later.

As Todd Woodbridge pointed out on Monday night, Hewitt's actions were actually against the rules. "The rules have changed," the Aussie great said on Channel 9. "You are allowed to coach but you can't do it from the other end. You can only do it at the same end. You can't go across the court."

Woodbridge also highlighted that de Minaur didn't really get the message and failed to capitalise on the small window of opportunity. The Aussie hit a number of balls straight back to Rublev and didn't even attempt a drop shot after that.

"He only had to try and get the ball going corner to corner and get Rublev moving," he said. "But it was amazing from Rublev in that he'd go bang on the serve, crank a winner or get the point where he could just stand in the centre. It was 'this close' to him not being able to finish the match."

Did Alex de Minaur rob himself of momentum?

De Minaur was dealing with an injury of his own and took a medical timeout in the third set for treatment on a blister on his foot. At that stage of the match he was up 3-0 in the third, and although he won the set Rublev had gotten it back to a tiebreaker.

John McEnroe suggested in commentary that de Minaur hindered himself with the timeout and halted his own momentum. Rublev went on to win a staggering 15 of the next 19 games.

"Surprising (de Minaur) takes a medical timeout with the roll he's on," the American legend said. "The negative is it gives (Rublev) the chance to regroup mentally, get his concentration back."

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