Yet any hint of final-day jeopardy surrounding the fixture - City still needed a point to be certain of qualifying for the Champions League - evaporated when they saw Watford's team sheet.

Hornets manager Mazzarri, having earlier in the week been told he would be out of a job after the game, appeared to have gone rogue with his final line-up.

Deprived of six centre-halves through injury, the Italian fielded two full-backs and midfielder Valon Behrami in the most makeshift of back-threes.

Yet even more bizarre was the sight of two goalkeepers named on the bench.

However, having three goalkeepers on the field would probably not have saved Watford from a mauling.

A horrid defensive mix-up and sliced clearance by Heurelho Gomes ended with Jose Holebas clearing a Jesus header off the line after just 50 seconds.

And within five minutes City were ahead when no one thought to mark Kompany from Kevin De Bruyne's corner and the City captain thumped a header past Gomes.

Aguero missed two presentable chances to double the lead but the second did arrive, in comical fashion, in the 23rd minute.

When Abdoulaye Doucoure slipped as the ball rolled past him in the centre circle, De Bruyne was able to stroll up the field unchallenged.

He slid the ball between Watford's so-called defence to Aguero, who had the simple task of tucking it past the exposed Gomes.

Aguero brought up 20 Premier League goals for the season 13 minutes later, when David Silva fed Leroy Sane who crossed for the Argentinian to help himself again.

To add to Watford's misery one of their few remaining defenders, Daryl Janmaat, was injured in the build-up meaning a debut for youngster Andrew Eleftheriou.

The teenager fitted into the chaos seamlessly, though, as Fernandinho waltzed through a succession of misplaced tackles to make it four before half-time.

The high farce continued after the break when Mazzarri received a lecture from referee Jon Moss, and Watford's fans began to call for him to be sent to the stands.

His team did show a bit of fight in the second half, though, with Stefano Okaka forcing a fine save from Willy Caballero with a fierce drive.

But normal service was resumed on the hour when Jesus stole in ahead of Tom Cleverley to hook Aguero's cross over Gomes.

Watford skipper Troy Deeney was left out of the starting line-up despite the injury crisis - again suggesting all was not well between him and Mazzarri.

The striker left the dressing room to warm-up alone at half-time and was sent on with his team 5-0 down, to the biggest cheer of the day from the home fans.

It was an acrimonious end to Mazzarri's year in charge but a satisfying finale - albeit not a particularly taxing one - for Pep Guardiola and City.