Red Bull team mates Daniel Ricciardo and Max Verstappen have pledged to stay friends, even if they end up being title rivals in 2018.
"I hope so," said Ricciardo when asked whether their friendship could survive a sustained championship battle. "Keep him on my birthday list!
"We said at the start of 2017 it would be a good problem to have," he continued. "If we're both fighting at the front and having some battles.
"If it's ultimately deciding a world title we would happily run with that challenge," the Australian added. "So, yeah, we'll see."
The pair have appeared to be on very good terms ever since Verstappen stepped up from the sister Toro Rosso team early in 2016. The only significant public disagreement between them to date came when the pair collided on the opening lap of last year's Hungarian Grand Prix.
However, the dramatically deteriorating relationship between Lewis Hamilton and Nico Rosberg during their four year partnership at Mercedes showed what the pressure of a sustained title battle between team mates can do.
"For sure when you fight for the World Championship it will get a bit more tense, I think, on the track," admitted Verstappen. The Dutch driver said that he and Ricciardo would continue to be friends "because we respect each other."
"At the end of the day, you always come back to where you respect each other," he continued. "You have to accept if one guy is faster than the other and I think that's what we can do.
"When somebody has a good race, we can really say to each other 'well done' and 'you really deserved that'. And I think that's also very important."
Verstappen won two races in 2017 and out-qualified Ricciardo on 13 occasions. However, Ricciardo came out on top in the drivers standings thanks to victory at Baku.
Even so, both drivers were a long way off their Mercedes and Ferrari rivals when it came to the championship battle.
"I believe in 2018 we will close the gap," Ricciardo insisted. "Is it enough to fight for a title? I think we can certainly get close but we'll see.
"I don't want to predict too early. I'm sure we've learned a lot and I believe we're going to put in the right work in the winter to start strong.
"And then that'll be exciting!"