Aleix Espargaro has apologised to his team after his costly blunder at the Catalan Grand Prix handed Fabio Quartararo a further advantage in the MotoGP championship.

Quartararo was cruising to first place on Sunday as title rival Espargaro seemed set to finish second in Barcelona.

But Espargaro inexplicably started waving to the crowd as he began the final lap, incorrectly believing the race had finished and he had secured second on the podium.

That ended a four-podium race streak for Espargaro, who slipped to fifth, and he sits 22 points behind leader Quartararo in the standings.

The Aprilia rider was quick to apologise for his mistake after the race as he explained he had misread the circuit's timing tower when keeping an eye on the lap count.

"I'm sorry. That's the only thing that I can say, sorry to my team. It's completely my fault," Espargaro told reporters.

"My people [with the pit board] were the first ones [out of the last corner], so I had no time to watch the lap. Some laps I had no time to look at the laps [remaining] and the gap with [Jorge] Martin.

"I was pushing to the limit so I just watched the gap with Martin, +0.6, then I watched the tower and I saw 'L1'. So I did one lap and then I didn't remember that here in Barcelona the last lap is 'zero' not 'one'. And I closed the gas on the straight.

"So I'm very sorry for my team because I didn't have the speed of Fabio to win. But if I want to beat him in the championship I cannot do these mistakes. Today, I lost nine points, so I'm very sorry."

Espargaro also believes he could have maintained pace with Quartararo but had been too worried about concerns surrounding his tyre management.

"Yesterday between Michelin and my team, everybody put a lot of worry into my [mind] by saying that I use a lot of tyres, that I had to be gentle on the first laps and I was too gentle sincerely," Espargaro said.

"Because at the end of the race, when I overtook Martin, I had enough tyre to put 41.5s and go away.

"I think Fabio was not faster than me, but he was smarter, was able to push at the beginning, and then it's impossible to recover two, two-and-a-half seconds to Fabio.

"I think I could have gone with him at the beginning. But anyway, it's too late."

Fabio Quartararo extended his MotoGP championship lead with victory in Sunday's Catalan Grand Prix as title rival Aleix Espargaro made a staggering and costly mistake.

Quartararo was a comfortable winner, and Espargaro looked nailed on for second place as he began the final lap, but the Spaniard thought the race was over and began waving to the crowd in Barcelona.

He was celebrating what he believed to be a podium finish, having started on pole position, but by slowing down he lost momentum and could not recover once he realised his clanger, trailing home in fifth.

Espargaro would have had good cause to celebrate second place, given he suffered abandonments in six of his previous seven appearances in this race, finishing only once when he was 12th in 2020.

The devastated Espargaro was later seen with his head in his hands by the side of the track and in the Aprilia garage. Nine points had slipped away, potentially crucial come the end of the season, with Quartararo boosting his championship lead to 22 points.

Quartararo and Espargaro were first and second at halfway, with a gap of around four seconds between the pair.

Espargaro slipped a place as Jorge Martin jumped to second, but the Aprilia man soon edged back ahead of the Pramac rider.

That looked set to be the 1-2-3 until Esparagaro's miscalculation allowed Martin to snatch second place, with Johann Zarco finishing third and Joan Mir fourth.

There had also been early drama, with Francesco Bagnaia (Ducati), winner of two of the last three races this season, crashing out on the first corner along with Takaaki Nakagami (LCR Honda) and Alex Rins (Suzuki Ecstar) after a shunt.

Enea Bastianini (Gresini), third in the championship, a place ahead of Bagnaia, also tumbled out of the race, with Quartararo's grip on first place tightening even before Espargaro's hapless error.

TOP 10

1. Fabio Quartararo (Monster Energy Yamaha)
2. Jorge Martin (Pramac Racing) +6.473 seconds
3. Johann Zarco (Pramac Racing) +8.385s
4. Joan Mir (Suzuki Ecstar) +11.481s
5. Aleix Espargaro (Aprilia Racing) +14.395
6. Luca Marini (Mooney VR46) +15.430
7. Maverick Vinales (Aprilia Racing) +15.975
8. Brad Binder (Red Bull KTM) +21.436
9. Miguel Oliveira (Red Bull KTM) +26.800
10. Alex Marquez (LCR Honda) +30.460

CHAMPIONSHIP STANDINGS

Riders
1. Fabio Quartararo (Monster Energy Yamaha) 147
2. Aleix Espargaro (Aprilia Racing) 125
3. Enea Bastianini (Gresini Racing) 94
4. Johann Zarco (Pramac Racing) 91
5. Francesco Bagnaia (Ducati) 81

Teams
1. Aprilia Racing 171
2. Monster Energy Yamaha 169
3. Ducati Lenovo 146
4. Pramac Racing 142
5. Suzuki Ecstar 138

Fabio Quartararo was left baffled as to why his leather race suit split open as he slipped from pole position to a fourth-place finish at the Catalan Grand Prix.

MotoGP championship leader Quartararo was aiming to seal back-to-back wins in Barcelona following his triumph on the circuit in 2020, but the Monster Energy Yahama driver slipped up early on and failed to finish on the podium.

Miguel Oliveira got Red Bull KTM's first win of the season, and the third race victory of his career, with Johann Zarco and Jack Miller completing the top three.

Quartararo was second until the final three laps, when Zarco made a daring overtake and caught the Frenchman out.

To complicate matters, Quartararo's suit had opened, with the 22-year-old's chest protector also slipping out.

He cut two corners as he battled with Miller for third, and was handed a three second penalty which cost him a third straight podium position at the Catalan Grand Prix.

"What happened I don’t know, I just know that I had the leathers completely open," he explained to reporters.

"I tried to just put it in a normal position again, I couldn't do it. So was difficult to ride, but unfortunately, it happens.

"It happened today, so Alpinestars is looking at how it's possible because at the end of the race it was possible to close it again.

"But it's like this, it was not our day but I can be happy with this fourth position… well, third, but finishing fourth."

Former MotoGP champion Casey Stoner tweeted his thoughts on the incident, insisting Quartararo should have been disqualified from the race.

"Well, I think I already have a penalty that I don't agree [with], demoted three seconds from P3 to P4," Quartararo said when Stoner's comments were put to him.

"I think this penalty is quite enough. It's finished, the race is finished, everything is safe.

"So, I think right now it's not enough to talk anymore because the race is finished. I think there's no point to talk anymore about these possible things."

It was a race which belonged to Oliveira, with the Portuguese rider holding the lead for 23 laps.

"The most difficult thing about the race was the mental ability to stay calm, it was so easy to be aggressive or to just override the tires at the beginning," he said in a news conference.

"I felt like that was the key, stay calm and the race will come to me."

Elsewhere in a frantic race, six-time MotoGP champion Marc Marquez crashed out on Turn 10, which also claimed Valentino Rossi and Aleix Espargaro.

Marquez has now failed to finish the last three races, a career first for the 28-year-old.