These two men first crossed paths in 1997 at Barcelona, when Arteta joined the famed La Masia academy, meeting his idol Guardiola - then club captain.
After retiring as a player in 2016, Arteta was given his coaching apprenticeship by Guardiola and he spent three years working under his mentor at Etihad Stadium.
A return to Arsenal followed the sacking of Unai Emery, and within five months he had won the FA Cup.
That was supposed to signal a return to regular silverware for the Gunners, but Arteta was finding it difficult to crack the Guardiola code. They were runners-up to City in the 2022-23 season - despite spending 248 days at the top - as well as in the following campaign.
Tensions between the two men began to appear in September 2024 when City salvaged a 98th-minute equaliser for a 2-2 draw against 10-man Arsenal, with then captain Kyle Walker accusing the opposition of employing "dark arts".
In a news conference the following week, Arteta was asked about that comment and replied, external he had "all the information, believe me".
Guardiola was none too pleased with that response, and said: "So, we have to [say]: 'OK you provoke me, OK, I'm there.' You want a war? Now we war."
It was a stark contrast to the Guardiola-Klopp era.
An injury crisis in defence derailed City's campaign, but Arsenal again finished second to Arne Slot's Liverpool.
The friction has cooled in the past year, with BBC Sport columnist Guillem Balague reporting that contact between Guardiola and Arteta had been re-established and the two were on speaking terms but "nobody wants to say who made the first call".
Nevertheless, Arteta was desperate to end his streak as a runner-up and his style of play became the antithesis to that of Guardiola's, with Arsenal scoring a record number of goals from set-pieces in their challenge for the title.
Despite being beaten by City in this season's Carabao Cup final, Arteta had the final say by finally clinching the title for the first time in over two decades following City's draw at Bournemouth.
"For Guardiola, he adapted to many rivals and changes in the Premier League," added Onuoha. "Looking back to 10 years ago, you can see how different he was then to how he became.
"There have been so many iterations of his side and different versions of the team in the Premier League.
"From an Arsenal perspective, they forced him to adapt but that came in line with changes in the league as it was very different a few years ago."
Where Guardiola ends up next remains to be seen, but he will be lining up not only his next job, but his next managerial adversary too.
