Andy Murray should hate Novak Djokovic.
The Serb has outclassed Murray 23 times in 32 meetings on the ATP Tour. Four of those wins have come in grand slam finals, so the Scot has every right to have a dartboard with Djokovic's face pinned up on his bedroom wall.
But that's not the case with these two.
They've known each other since before they were teenagers and have grown up on the professional circuit together since the early 2000s.
It's why, regardless of the frustration the loser must feel after any of their matches, there's a respect that isn't easily broken.
Never was that respect more evident than during Djokovic's three-set win over Murray in the final of the Madrid Masters on Monday morning, 6-2 3-6 6-3. Djokovic was serving at 30-all at 4-2 in the third before he received a time violation warning. Then Murray interjected and took the blame himself.
"I was the one keeping him waiting. I made him wait. He was ready five seconds ago," Murray said.
It's rare to see such acts of sportsmanship in professional tennis, and especially so from a man known for moping, moaning and whingeing on the court.
Murray has a history of complaining to umpires about his opponents' time wasting too, like in his loss to Rafael Nadal in April's Monte Carlo Masters. He told the chair umpire it was "fascinating what you let some of these guys get away with" before the man in charge accused Murray of having "zero respect for me".
But when Djokovic is involved, Murray is less likely to blow a top.
"It was truly something that is unusual, honestly, to see at the highest levels," Djokovic said of their good-natured rivalry.
"I always like to look back at those moments and take that as a highlight rather than only results and rivalries and who wants to beat who more and stuff like this.
"I think it's nice to see in the midst of this important match that you're showing your human side and expressing your character values that unfortunately in this sports society are not seen often.
"I'm glad we have done that and sent the right message to many young kids and tennis players."
The honours went to Djokovic in the Spanish capital just as they did in their first match as pros a decade ago in the third round of the Mutua Madrid Open.
They are ranked number one and three in the world, respectively, and both are grand slam champions (Djokovic with 11, Murray with two). Djokovic said it was evident from their early days that both would do whatever it took to reach the pinnacle of tennis.
"Ten years later, we are the two best players in the world," said Djokovic.
"At that time maybe it seemed like something that will be very challenging for us to achieve. But we both strive to be at the top and we've known each other since we were 12. I think you can see already in those junior days that both of us have serious intentions to conquer the tennis world and try to make a serious mark.
"I'm very pleased that I have developed a great rivalry with somebody that I've known for a very long time and somebody that I have a very good and friendly relationship with on and off the court."
It's not always like this though. Take the lack of empathy shown towards Maria Sharapova from her colleagues in the wake of her doping scandal, when opponents weren't shy in criticising the Russian for her cold locker room demeanour.
Then there's the revelation from Djokovic's coach Boris Becker - made in his autobiography launched last year - that he and Roger Federer act out a "fake" friendship in public but really dislike each other behind the scenes.
And of course, we can't imagine Stan Wawrinka letting Nick Kyrgios take as much time as he likes between points after the Aussie made a crude remark about his girlfriend last year.
That's why the bond between the two veterans is so unusual - in a positive sense.
Competitiveness can breed selfishness and with that, jealousy and resentment - especially when one person has the ability to crush your dreams in the space of five (or fewer) sets. But that's never eventuated between these two men, and it's something they, and the sport, should be proud of.