THE smallest man on the pitch won one of the worst Manchester derbies in living memory as Pep Guardiola’s fallen champions continued on their journey down the gurgler.

With City leading after 88 minutes through Josko Gvardiol’s first-half header, Amad won a penalty which was converted by Bruno Fernandes, then netted a dramatic late winner.

Amad Diallo inspired a stunning Man Utd comeback

He scored a brilliant winner in the 90th minute to spark huge celebrations

Amad took it round Ederson and finished calmly minutes after winning a penalty

Bruno Fernandes converted the spot-kick to equalise

Pep Guardiola was left scratching his head again

It meant Guardiola’s side have won just once in their last 11 games and are now below Nottingham Forest, the only team they have beaten during this horror run, and out of the Champions League places.

For United boss Ruben Amorim, this was a remarkable victory, after he had ditched Marcus Rashford and Alejandro Garnacho from his matchday squad in a show of early ruthlessness.

This was a Manchester derby which had been billed as the worst in decades and it pretty much was the worst in decades until Amad stole the show.

Pep Guardiola’s crumbling empire was pitted against the ancient ruins of Sir Alex Ferguson’s dynasty and you couldn’t see any world-class quality for dust.

Two clubs which boast 21 titles of the 32 Premier League seasons contested are wallowing in mediocrity right now.

United’s teamsheet seemed to suggest the answer – no Rashford or Garnacho – with Amorim refusing to offer up any dodgy sicknotes.

United had their young star to thank

After back-to-back league defeats, United had been buoyed slightly by a Europa League win over Viktoria Plzen, who most of us assumed was ranked No17 on the WTA Tour.

For half an hour it just advertised – two poor teams – with United marginally the better of them.

Although it might have helped them if Amad had been onside at any point.

Mason Mount, whose luck with injuries has been horrible, hobbled off after 15 minutes to be replaced by Kobbie Mainoo.

Phil Foden, the Footballer of the Year who hasn’t scored a Premier League goal all season, drilled one wide from 20 yards.

City were ragged and passive until, suddenly, they were a goal ahead.

De Bruyne took a short corner to Ilkay Gundogan and a return pass before his deep cross took a ricochet on its way to Gvardiol, who leapt behind Diogo Dalot to power home a header.

After this brief burst of pride, City’s skipper Kyle Walker plunged his team back into shame.

While rutting heads with Rasmus Hojlund, Walker went down like a sack of spuds, sparking a mass bout of handbags and the genuine ire from the full-back’s long-term England team-mate Harry Maguire.

Kyle Walker went down after a soft clash of heads with Rasmus Hojlund

Yorkshiremen are not supposed to act like this, Maguire might have said. Although it was probably less polite than that.

Foden, looking a little more like last season’s model, then wriggled past Manuel Ugarte and Lisandro Martinez before his shot was deflected wide off Maguire.

But the first-half was best summed up by a schoolboy pass from Dalot across his own penalty area, which went straight to Foden, who couldn’t control it.

After the break, if anything, the quality got even worse.

The quality worsened after the interval.

City chose to give Amad, the smallest player on the pitch, a free header, forcing Ederson into a full-stretch save to turn it around the post.

Mostly, however, either team struggled to thread three passes together.

De Bruyne, our best chance for a world-class performance, missed a long-range shot and was replaced by Mateo Kovacic.

Unexpectedly, United engineered a coherent move.

Noussair Mazraoui dashed forward and supplied Hojlund, who unleashed Fernandes with a wonderful through pass.

The United captain skillfully chipped Ederson, but his shot flew wide of the far post.

United deserved a point. It never seemed unlikely that they would accomplish enough nice things in a sequence to score a goal.

Until, suddenly, they scored twice in two minutes.

The first was a personal disaster from Matheus Nunes, whose back-pass was intercepted by Amad.

The little fella rounded Ederson and as he turned, the recovering Nunes stood on his foot.

Ref Anthony Taylor pointed to the spot and Fernandes thumped home.

Next, Martinez delivered an expert pass from the deep, and Amad shot between City’s central defenders to meet it.

He lobbed Ederson, volleying home from an angle as Walker failed to cut it out.

It was largely terrible but the finale was simply extraordinary.

Josko Gvardiol headed home to make it 1-0

Mason Mount came off injured after 14 minutes