Novak Djokovic argued with the umpire and roared with delight as the Serbian brushed aside Ernests Gulbis to reach the last 16 at Wimbledon.
Djokovic came back from a break down to win the opening set and from there his victory was never in doubt as the 12-time major champion won 6-4 6-1 7-6 (7/2).
The world number four, however, apologised after the match to umpire Jake Garner, whom he had told to "focus" after seeing two early challenge requests rejected.
More ominous for his rivals, however, was that Djokovic seemed to have some of his old fire back on Centre Court, yelling in celebration as he stormed clear in the decisive tie-break.
Djokovic will now face France's Adrian Mannarino, who was a surprise winner earlier on Saturday against compatriot Gael Monfils.
The collision with Garner came before even three games had passed as Djokovic twice tried to challenge a call and each time was informed he was too late.
An angry Djokovic said: “That’s two points in a row, beginning of the match. Focus, please.”
Asked afterwards about the disagreement, Djokovic told the BBC: “Maybe it was not the right words to say, I apologise. It was just very odd in the third game two situations where I thought the call should have been different.
“But he is trying to do his job the best he can, I am too. In the heat of the moment you exchange things and I think we will be fine.”
The display of irritation might make wary those predicting Djokovic will win a fourth Wimbledon title next weekend, but after reaching his 10th fourth round here he is yet to drop a set.
“I am delighted with the performance,” Djokovic said.
“I thought I raised the level of tennis compared to the last couple of matches and last couple of weeks. It was the most focused I was on court and at the right time.
“Gulbis presents a great challenge. He is very unpredictable, he has a huge serve at 125, 130 miles per hour and on grass it’s not easy against a big server like that.
“He started very well. He was a break up and I managed to win seven or eight games in a row, which gave me lot of confidence. In general I’m very pleased with how I felt I played.”
Gulbis, rated in the top 10 only three years ago, has plummeted to 589th due to a combination of fitness and commitment issues but the Latvian was able to enter the main draw at SW19 with the help of a protected ranking.
He started well, capitalising on his opponent’s early angst to break and lead 3-1, but a trademark backhand pass prompted Djokovic to fight back.
Serving to stay in the set, Gulbis missed three simple forehands and Djokovic pounced to win his fourth successive game and move one frame clear.
Four became nine in the second as Djokovic led 5-0, and at the end of the set Gulbis took a medical time-out for treatment on his back.
He offered more resistance when he returned but Djokovic proved too strong in the tie-break as another errant forehand confirmed his progress after two hours and 13 minutes.
Roger Federer joined his fellow title favourites in cruising into the fourth round with victory over Mischa Zverev.
Defending champion Andy Murray is the only one of the big four to have been tested so far, and Federer matched Djokovic and Rafael Nadal in reaching the last 16 without having dropped a set.
Zverev certainly played his part in the match and briefly had Federer under pressure late in the first set.
But, once the third seed won the tie-break, he was never troubled and eased to a 7-6 (7/3) 6-4 6-4 victory in an hour and 49 minutes.
All parts of the Federer game look to be working well ahead of a fourth-round match against Grigor Dimitrov, with the Swiss finishing on a tally of 61 winners and only seven unforced errors.
History did not favour Zverev. This was their fifth meeting, with the German yet to win a set. In Halle in 2013 he did not even manage a game, while their two matches this season were closer but not that close.
It has been a remarkable rise for Zverev, inspired by the success of little brother Alexander, from outside the top 150 only a year ago.
One of the few genuine serve-volleyers left in the game, Zverev stunned Murray in the fourth round of the Australian Open before losing to Federer.
Things had a familiar feel early on as Federer raced into a 4-1 lead but Zverev began to rush the seven-time champion and the German fought back to level.
He had Federer under real pressure at 5-5, forcing two break points, but he could not take either and was second best in the tie-break.
Federer just had a little too much pop on his groundstrokes for Zverev’s fine volleys to withstand, while the German struggled to put any real pressure on his opponent’s serve in the second and third sets.
After breaking early in the third, Federer brought out the tweener, much to the delight of the crowd – although it did not win him the point.
There was a bit of an exhibition feel about Federer in the final stages before he clinched victory with his 13th ace.
