Jose Mourinho is one of the most decorated football managers of all-time.
However, to be successful in most things in life, there must be challenges and enemies to overcome along the way. It's been no different for Mourinho. The Portuguese manager has been successful at every club he's been at, but now faces the challenge of bringing silverware to a trophy-hungry Tottenham side - but he's already been having run-ins with his ex's partner (Manchester United manager Ole Gunnar Solskjaer).
Here's how Mourinho's biggest managerial rivalries rank.
1. Pep Guardiola
Key Quote: “When you enjoy what you do, you don't lose your hair, and Guardiola is bald. He doesn't enjoy football.”
It's been gripping to see Mourinho and Pep Guardiola go head-to-head over the years at different clubs.
Perhaps the most iconic was when Mourinho's Inter side beat Barcelona to reach the 2010 UEFA Champions League final, which they went on to win.
Since then, the pair have battled it out in the red and blue corners of Manchester, where Mourinho's Manchester United famously overcame a 2-0 deficit at half-time to beat Manchester City 3-2 at the Etihad Stadium in 2018.
While Guardiola remains at City, Mourinho is now the boss at Tottenham, where he had the last laugh when his side beat City 2-0 in February.
2. Rafael Benitez
Key Quote: "How many championships has Benitez won since he joined Liverpool? None. And how many names were suggested by the press to replace him? None."
Perhaps it wasn't as tense when Mourinho managed Manchester United and Rafael Benitez managed Newcastle a few years ago, but these two had such intriguing battles when managers of Chelsea and Liverpool respectively.
While Mourinho's men would usually triumph in the league, it was Benitez's Liverpool who got the better of Chelsea in the UEFA Champions League meetings.
3. Arsene Wenger
Key Quote: "If he is right and I am afraid of failure it is because I didn't fail many times. Eight years without silverware, that's failure."
It's one thing talking about battles on the pitch, but it turned into a physical battle on the touchline between Mourinho and Arsene Wenger when Arsenal met Chelsea at Stamford Bridge in 2014.
The fourth official had to separate the pair as Mourinho's side went on to win 2-0, although the most recent meetings between the two had a much nicer feeling.
Mourinho greeted Wenger with a commemorative retirement gift prior to Manchester United's win against Arsenal in 2018, and the pair sat side-by-side to provide analysis for beIN Sport's coverage of the 2019 UEFA Champions League final.
4. Antonio Conte
Key Quote: "What never happened to me - and will never happen - is to be suspended for match-fixing. That never happened to me and will never happen."
How times have changed. From prowling the Stamford Bridge touchline during his Chelsea heyday, Mourinho came head-to-head with Antonio Conte on his return to west London.
The former Italian Chelsea boss was accused over-celebrating and was dubbed the 'clown on the touchline' by Mourinho when his side thrashed Manchester United 4-0. Conte was also triumphant in an FA Cup final against his Portuguese counterpart.
5. Ole Gunnar Solskjaer
Key Quote: "He would never accept to play with a 17-yard box, I think he would prefer a 22-yard box! For him it would be better."
While this is a relatively new rivalry, it's still bubbling away ahead of Tottenham's trip to Old Trafford on Sunday.
Ole Gunnar Solskjaer took over from Mourinho when the Portuguese was sacked by the Red Devils in 2018. Since then, Mourinho's Spurs side have lost 2-1 and drawn 1-1 with Manchester United.
Solskjaer recently made a jibe at Mourinho's goalpost remark after Spurs' UEFA Europa League tie in North Macedonia, to which Mourinho responded by suggesting Solskjaer would enjoy playing with a 22-yard box instead of an 18-yard box in reference to the amount of penalties United receive.