BAKU, Azerbaijan — As Daniel Ricciardo celebrated winning a hectic Azerbaijan Grand Prix on Sunday, title rivals Lewis Hamilton and Sebastian Vettel clashed in a bitter incident that could shape the rest of an intriguing Formula One season.

Hamilton accused Vettel of "disrespectful" driving after the four-time champion pulled alongside Hamilton and appeared to deliberately swerve into him when they were behind the safety car approaching the midway point of a stop-start race.

"Ultimately what happened today was disrespectful. It’s not deserving of that reaction from someone you have respect for," Hamilton said. "A multi-world champion should behave better than that. It’s what you expect in go karts. That’s not how you drive."

Vettel, who is chasing a fifth world title to stop Hamilton winning a fourth, was given a 10-second time penalty for the incident. Hamilton, less angry in his media briefing than immediately after the race on television, maintained Vettel shunted him on purpose.

"It couldn’t be clearer. It’s clear as blue skies," the British driver said. "Some people don’t like to own up to their own mistakes."

After eight races of a see-saw season, Vettel’s Ferrari leads second-placed Hamilton’s Mercedes by 14 points — 153 vs. 139. They have won three each and — over the first seven races — both had spoken at length of their huge admiration for each other.

But this is the first time they have been main rivals for the title, and the pressure is showing.

"Today wasn’t fair play. Today was obviously a different Sebastian we’re seeing," Hamilton said. "I like to think that I remain respectful and I’ll continue to do so. I want to win the championship the right way."

BREAKING: At 18 years, 239 days old, Lance Stroll is the 2nd youngest driver in F1 history with a podium finish (3rd at Azerbaijan GP) pic.twitter.com/AmE3RtascX — Sportsnet Stats (@SNstats) June 25, 2017

Ricciardo secured his fifth career win, while Mercedes driver Valtteri Bottas overtook 18-year-old Canadian Lance Stroll’s Williams in the closing meters to take second place.

Vettel finished fourth, while Hamilton was fifth.

The safety car came out three times in quick succession before a red flag stopped the race on lap 22 of 51 because debris littered the track.

Shortly before that, the Hamilton-Vettel incident occurred.

While behind a safety car, Hamilton, who was in the lead, appeared to slow his car right in front of Vettel — causing Vettel to drive into him. An irate Vettel then accelerated alongside Hamilton, gesticulated and moved his car to the right and into him.

Vettel thought Hamilton had slammed the brakes on intentionally — which is known as brake-testing — which Hamilton denied.

"The stewards looked at my data," Hamilton said. "Clearly I didn’t."

Speaking on Britain’s Channel 4 television just after the race, Hamilton went as far as to say that Vettel "disgraced himself," adding that "if he wants to prove he is a man we should do it out of the car."

But Vettel maintained that Hamilton was just as much to blame.

"If I get a penalty then we should both get a penalty," the German driver said. "He did something similar a couple of years ago in China at a restart. It’s just not the way to do it."

Despite Vettel’s time penalty, Hamilton lost valuable time of his own — and possibly the race — changing a loose headrest.

Hamilton was on Vettel’s tail on the last lap, but could not overtake.

The fact Ricciardo won from 10th on the grid, and that Bottas clawed his way back from last following an early incident, summed up one of the most bizarre races for years.

It was also a superb performance from Stroll, the son of a billionaire, who faced heavy criticism earlier in the season.

"I’m just lost for words," said Stroll, from Montreal, who earned his first podium finish. "It’s beyond amazing."

Ricciardo, as he likes to do on the podium, took off one of his race shoes and filled it with Champagne. Then he passed the shoe to Stroll, who — barely old enough to drink — took a swig of bubbly mixed with sweat.

At least the chilled drink cooled him down, for when the race started at 5 p.m. local time the track temperature was still a roasting 53 degrees Celsius (127 Fahrenheit).

Hamilton was on pole position for the 66th time, with Bottas next, followed by Kimi Raikkonen and Vettel fourth.

Hamilton got away cleanly, but Raikkonen clipped Bottas and bumped his own Ferrari into the wall, and Vettel surged past them into second place.

But Bottas had to pit on the second lap for a new front wing, dropping to last.

Up ahead, Hamilton asked over the radio where Bottas was, perhaps concerned his teammate would not be able to protect him from Vettel later in the race.

They would clash soon enough.

Elsewhere, the 6-kilometre (3.7-mile) Baku street circuit — with its long straights and tight, hard-braking corners — took its toll.

Max Verstappen failed to finish for the fourth time in the last six races; while Raikkonen, Felipe Massa, Sergio Perez and three others had to quit.

In a rare bright spot for McLaren, Fernando Alonso placed ninth for his team’s first points of a frustrating season.

But all the talk was about the Hamilton-Vettel incident with the Austrian GP next.

Vettel said he planned to phone Hamilton before the July 9 race.

Maybe he shouldn’t bother.

"Firstly, he doesn’t have my number," Hamilton said. "I do my talking on the track."