Ten-man Benevento inflicted misery on AC Milan for the second time this season as a 1-0 win at San Siro on Saturday momentarily prolonged their fight against relegation.

Needing three points to remain a remote mathematical chance of avoiding the drop, the visitors grabbed exactly that as Pietro Iemmello's first-half strike secured a memorable fifth victory of the campaign and the club's first away from home in Serie A. 

The result was threatened by a late second yellow for substitute Cheick Diabate, but the bottom side held on to secure a result that bore resemblance in its significance to the teams' dramatic 2-2 draw in December, Benevento on that occasion claiming their first Serie A point in what was Gennaro Gattuso's maiden match.

And the underdogs had equal reason to celebrate this time around, taking full advantage of a charitable Milan performance that almost began with them falling behind to what would have been a comical own goal.

The Rossoneri, now winless in six league matches, did not avoid embarrassment for long, Iemmello netting in the 29th minute.

Franck Kessie did hit the crossbar after the interval, but, despite their numerical advantage in the closing stages, Milan slipped up once more and are now at risk of being leapfrogged by seventh-placed Atalanta, potentially leaving next month's Coppa Italia final against Juventus as their best route to Europa League qualification.

Gattuso recalled Andre Silva for his first start in five matches and the striker should have done better with an early opportunity, completely missing his finish after Fabio Borini's low cross in from the right broke promisingly.

It was a rare moment of life in a sleepy start from the Rossoneri that almost left them red-faced in the 15th minute, Gianluigi Donnarumma forced into a scurrying clearance off his line from Ricardo Rodriguez's wayward back-pass.

Instead, Benevento took it upon themselves to stir hope of an upset just shy of the half-hour mark. Nicolas Viola poked a clever pass through a static defence and Iemmello, ever so marginally onside, rolled a calm finish inside the near post.

Milan sought an immediate response to the setback as Patrick Cutrone volleyed over a difficult chance before Giacomo Bonaventura twice tested Christian Puggioni from outside the box.

Suso was called off the bench fewer than four minutes after the interval in a sign of Milan's intent, although it was at the other end that Danilo Cataldi curled a threatening effort marginally around the far post.

Franck Kessie soon went closer with a thunderous strike that crashed back off the crossbar, while the persistent Bonaventura unfurled another two attempts that were capably dealt with by Puggioni.

And the veteran goalkeeper continued to bail out his side under increasing pressure, impressively blocking a goal-bound Cutrone header.

Benevento's nerves were heightened by Diabate's dismissal with 10 minutes to play, the striker picking up two yellows in six minutes – the second for a stray arm on Leonardo Bonucci – but Roberto De Zerbi's men impressively negotiated the remaining moments to come away with another historic result.