Spanish Grand Prix winner Lewis Hamilton says he could tell Formula 1 title rival Sebastian Vettel was angry over being defeated at Barcelona.
Their race-long battle included Vettel jumping Hamilton at the start and the two making slight contact at Turn 1 after Vettel exited the pits alongside the Mercedes driver.
How Hamilton won a race he seemed to have lost
Hamilton ran an alternative strategy, picking medium tyres for the middle stint while Vettel held them off until the end, and also benefited from pitting just as a virtual safety car period was ending.
The race was ultimately decided when Hamilton, now back on softs, overtook Vettel's medium-shod Ferrari in the final stint.
"I could sense he was angry and he said he was angry," said Hamilton of Vettel.
"He drove a fantastic race but I can understand how he feels.
"We're never going to be happy to finish second, and I'd be concerned if he was because that's not what we exist for."
When asked if the title battle with Vettel, whose lead was slashed to six points after Barcelona, would impact their still-cordial relationship if they kept going wheel-to-wheel on track, Hamilton said: "I don't know, it's difficult to say.
"We just had a close battle and if it had gone a different direction then obviously it could be different.
"We know how racing goes, if he had hit me at Turn 1 and I didn't finish the race and he did, it wouldn't be 'great job Sebastian!'
"It was aggressive but I was able to remain in the fight fortunately and I avoided a collision ultimately.
"We'll have a tough fight and I love a challenge.
"He was respectful and that stayed the same even at the end."
Hamilton, who has spent the last three seasons fighting team-mate Nico Rosberg for the title, said fighting a driver in a rival team and a good relationship with team-mate Valtteri Bottas is making this championship fight one of his best.
"It's definitely one of the favourites if not the favourite [battle] I'm having," said the three-time world champion and two-time runner up.
"I'm in a much better position than last year so 2017 is a much better year so far.
"It's great to have a battle and a fight with another team is so much nicer and more enjoyable because there's no tension within our team.
"In the last race when Valtteri won there wasn't an ounce of me that was like 'damn it he won.'"