Pep Guardiola had just given a ball-boy a ticking off for returning the ball too sluggishly when he kicked his seat in the dug-out in frustration as the halftime whistle sounded.
Manchester City was leading Crystal Palace 1-0 but you'd never have known by the actions of its coach.
"The ball-boy was slow, everybody was slow," Guardiola said.
He was a lot happier at fulltime, though, with City having wrapped up a 5-0 win in its latest devastating attacking display in the English Premier League.
City has 16 goals in its last three league matches, and has a club-record 21 for the season after six games. At the current rate, this City team is rivalling Guardiola's Barcelona and Bayern Munich sides for entertainment and efficiency in front of goal.
"I must say," Guardiola said, "we are still in September. But I'm not telling [people] not to be excited. This is a show ... The biggest satisfaction is to see the fans come here and be happy."
The Premier League might never have seen attacking riches like the ones Guardiola has at his disposal, and last-place Palace - still without a point or even a goal this season - couldn't cope.
Gabriel Jesus wasn't even needed off the substitutes' bench for City, which broke Palace's stubborn resistance in the 44th minute through Leroy Sane and picked off the visitors with ease in the second half.
Sane led the rout, setting up Raheem Sterling for the second goal and Sergio Aguero - for the 300th club goal of his career - for the fourth. Sterling finished with two goals and substitute Fabian Delph curled in a shot from the edge of the area for the best of the lot in the 89th.
"When they take the lead," Palace manager Roy Hodgson said, "they are capable of showing the full register of their qualities.
"We've been given a headache, and now we have to find the aspirins."
It threatens to get even worse for Palace, which must play Manchester United, Chelsea, Newcastle and Tottenham in four of its next five fixtures.
And Christian Benteke, the club's only senior striker, hobbled off with what Hodgson said could be knee ligament damage.
City has an injury concern of its own after left back Benjamin Mendy went off with a right knee injury in the first half, but that was the only negative on another brilliant attacking display.
Such was Guardiola's lust for goals that he took off John Stones, a centre back, and sent on Delph for the final 20 minutes. With Delph's late goal, City became the first side to score at least five goals in three straight top-flight games in the same season since Blackburn in 1958-59.
Sane was City's star player, showing energy, trickery and an end product to delight Guardiola, who left out the winger in the first few games of the season after he failed to return from preseason in good shape.
After scoring twice in City's League Cup win over West Bromwich Albion on Wednesday, Sane put City ahead when he played a one-two with David Silva, poked the return ball over defender Scott Dann, and placed his finish between the goalkeeper's legs.
Sane delivered a low cross to set up an easy tap-in in the 51st for Sterling, who then scored from close range from Sergio Aguero's cushioned volley in the 58th.
The highlight of Sane's display was arguably his powerful, whipped left-wing cross for Aguero's 176th City goal, leaving the striker one goal behind Eric Brook's all-time record.
Sterling has scored in each of his last five league games, giving Guardiola yet another attacking option.
"Now I have five strikers," he said, ominously, "and all of them deserve to play."