Within just a handful of games, 26-year-old Rublev’s frustrations had already started to boil over, the first signs of his brewing anger showing as Dimitrov broke for a 3-1 lead.
In the following game, the sixth seed slammed his racquet against his shoes and drew blood from his own hand after an error before his opponent consolidated his break.
Rublev called the trainer on to see to the bleeding cut on his left hand at the change of ends and, still troubled by his self-inflicted injury, failed to convert three break points in the next game.
And as Dimitrov served out the opening set, the Russian screamed at the ground, the crowd on Arthur Ashe Stadium stunned into silence by his latest outburst.
The second set looked to have brought a calmer Rublev. In the opening game, he had his back against the wall at three break points down but stayed focused as he fought back to hold.
But after missing two break points of his own in the fourth game, he missed what should have been a sitter of a volley for the advantage and started furiously ranting, the sound amplified under the closed stadium roof.
Despite his irritation, Rublev was playing well and finally got the break he had been seeking for 5-3 as an error-strewn Dimitrov buckled under relentless pressure with multiple double faults.
But Rublev was left laughing in disbelief at his own mistakes as he let slip a 30-0 lead when serving for the set and allowed his opponent the immediate break back.
More errors then creeped in in the tie-break, the Russian squandering a 3-1 lead as six successive points went Dimitrov’s way to wrap up the set for the Bulgarian.
It was at that point that Rublev’s mentality seemed to switch, and in the third set, Dimitrov started to wilt and found himself a double break down as his much calmer opponent mounted his comeback attempt.
And though Dimitrov put up more of a resistance in the fourth set, it quickly went the same way as Rublev forced a decider, just as he had against France’s Arthur Rinderknech in the second round.
The tables turned in the fifth set, however, as Dimitrov found another level and the unforced error count started to rise for Rublev.
He sealed the deal by serving out the match to love, a Rublev backhand finding the net to give Dimitrov an eighth Grand Slam quarter-final berth.
