The Canadian Grand Prix was the race in which the Formula 1 title battle finally came alive this year.

It was also, however, the race in which it took a potentially decisive turn, putting a huge dent in George Russell's hopes of beating his 19-year-old Mercedes team-mate Kimi Antonelli to the championship.

Russell's retirement from the race came after 30 laps of frenetic battling between the pair which lit up the Circuit Gilles Villeneuve on a damp, gloomy day so cold it tempted world champions McLaren into a seemingly inexplicable decision to start the race on a dry track on wet-weather tyres.

The Briton's retirement handed the win to Antonelli, his fourth in a row, and the Italian now has a massive 43-point lead.

Doubtless there are many twists and turns to come in the remaining 17 races. Even so, that will take some recovering.

Afterwards, Russell was stoic but understandably downbeat.

"Right now it's his to lose," he said. "He is so many points ahead. It feels like the gods don't want me to be in this fight, when I look at the safety-car timing in Japan, breaking down in China Q3, fighting for pole, breaking down from the lead here today.

"But, you know, the pressure's off. Go out, enjoy every single race. Try to win every single race. And I've got nothing to lose.

"I don't want to be stood here talking like that. It is, of course, frustrating, but I want to be in that fight. Hopefully, the luck will turn."

Russell's references to luck refer to a series of situations where the dice have very much fallen in Antonelli's favour.

Two separate technical problems in qualifying in Shanghai prevented him fighting for pole. Antonelli took it instead, and his first win followed.

In Japan, Russell had been running second to McLaren's Oscar Piastri in the early laps, while Antonelli fought back after falling to sixth with a slow start.

The safety car came out after Russell had made his pit stop and before Antonelli had made his, handing the lead to the Italian on a plate, and leaving Russell a frustrated fourth.

And now this.

It was far from a foregone conclusion that Russell would have converted his lead into a win in Montreal. The two had fought so hard for so long, and were running together at the time, the fight having cooled a little after they had both been warned the team would step in if they did not tidy things up after some incidents that team boss Toto Wolff felt were too close for comfort.

But the suspected power-unit failure that stopped Russell ensured the points swing was enormous rather than manageable, even if Antonelli had been the one who came out on top.

For Russell, it was especially galling that it came after a victory in the sprint race on Saturday - after another tense and tight scrap with Antonelli - that had stemmed the Italian's recent momentum a little.

'I've not had a battle like this in years'

The battle Russell and Antonelli staged was gripping.

After reclaiming first and second places from the fast-starting McLaren of Lando Norris, they exchanged places several times, often as a result of one or the other of them locking up at the hairpin while trying to race on tyres that were too cold.

"I loved it," said Russell. "I thought it was great. I've not had a battle like this in years. I haven't seen a battle like this, probably, since Lewis [Hamilton] and Nico [Rosberg] in Bahrain 2014. And these new cars allow you to do that. These new engines allow you to do that.

"I don't know why anybody wants to change them, because we had amazing battles in Melbourne. We had great battles in China. Kimi and I have had a great battle today and yesterday, and that's only possible because of how these power units are."

Russell did not see there was anything wrong with it.

"We know how we need to race," he continued. "I think we both had it under control and it was great. I really enjoyed it. It was exceptionally difficult, this circuit, to break that one-second overtake mode."

Antonelli described it as a "really fun battle, really close".

The team were enjoying it, too - but only up to a point.

Eventually, when Antonelli ended up locking up on the outside of Russell on lap 24 at the chicane and went through the run-off area, their engineers came on the radio and warned them that if they couldn't tidy it up the team would call off the fight.

This will lead to some discussions between Wolff and the drivers over the coming days.

Wolff said: “It's always easy at the end now to say 'well that was great for the team and great for the sport and didn't we all enjoy watching the battling?' And that is true to a degree.

"But there is another side which we need to look at and that was it was close a few times. Kimi tucking back in and locking the tyres could have ended in a double DNF and not because of, you know, over-aggressive driving each other, simply by mistake.

"So it's important to analyse the race and discuss with the drivers whether they think it was a bit close and, if that is the case, how can we avoid these very, very tough situations or situations where we've been a little bit too close.

"As much as we look very sportsmanlike today, allowing it, there could be a situation where we would maybe turn it down a notch."

'He's not going to give up that fight'

Wolff was also not happy with some of the radio messages from the drivers, especially Antonelli, who had called for a penalty for his team-mate in the sprint, and also accused him of "pushing me off" in the grand prix.

Russell, too, was admonished by Wolff when he made a sarcastic comment about the location at which Antonelli had chosen to give back the lead after skipping the chicane.

"Obviously when you listen to some of the radio comms, I think there is room for improvement," said Wolff.

As for Russell's title hopes, Wolff said there was no reason to panic.

"Things have been going against him in the last few races," he said. "Today certainly would have been big points to collect. He was in the lead.

"But, if there's one guy that I would choose on this paddock in terms of resilience and determination, that would be George.

"He's had to overcome adversity previously, whether it's from karting or junior formulas. And he's not going to give up that fight. There's 17 races to go. So many points to score.

"So, yeah, this is just, you know, wake up tomorrow and digest, forget, move on, move forward and drive the best you can. And that's exactly what he's got to do."