Red Bull boss Christian Horner has lashed out at the fans who continue to boo Formula One championship leader Sebastian Vettel, suggesting that they are hurting the young German's feelings.
Horner said it was unfair to boo Vettel, who has suffered repeated ill-treatment this year and was again subjected to loud chants and heckles after winning the Singapore Grand Prix.
The 26-year-old star did his best to shrug off the jeers but Horner said the booing, blamed on a particular group of fans, might be getting under his skin.
"There is a small collective group and it is like a pantomime, but it is so unfair because it is not sporting," said Horner.
"The boy today has driven an unbelievable race. What you have witnessed today is one of the best drives that I have seen him produce in terms of raw pace, and I just don't think it is sporting to see a driver who has put in a performance like that not to get the reception he deserves.
"He is a great kid. He has a great sense of humour. He has a big heart at the end of the day."
Booing erupted after Vettel's wins in Belgium and Italy, and surprisingly at the less partisan circuit of Singapore, as Vettel moved closer to a fourth straight world title.
The opprobrium has been put down to plain boredom from fans, as the German has won more than half the races this season and already has one hand on the championship trophy.
On Sunday night, he led from pole position to the chequered flag in an astounding, if not terribly viewer-friendly, demonstration of uncatchable frontrunning.
"When you have a guy who is becoming almost a serial winner, it becomes like when people watched Muhammad Ali, they wanted to see who would beat him," Horner said.
"That is the case at the moment; people want to see who is going to beat Sebastian."
The team principal added: "He has got a broad set of shoulders but like anyone he has feelings and I don't think it is right."
Vettel blamed the jeering on a travelling contingent of hard-core Ferrari fans.
"It's not nice but I think you should look around the grandstands. Most of the fans are dressed in red," he said after the victory, referring to Ferrari's team colour.
"They're quite emotional when they're not winning and if somebody else is winning they don't really like it.
"And as it seems in a sense they are on a tour, they're wealthy enough to go to a lot of races at Monza or take the flight to come to Singapore."
Vettel admitted he hadn't given the crowd the "most exciting race" after setting off from pole and completing 61 laps of the Marina Bay circuit unheaded.
But he insisted the boos did not bother him - as long as he was able to keep winning.
"As long as they keep booing we're doing a very good job, that's the way I see it," Vettel said.
"Obviously I didn't give them the most exciting race - but on days like this, I really don't mind."