Saints took the lead in the first half with what went down as an own goal by Fred, who saw Che Adams' shot strike him before finding the corner of the net at St Mary's Stadium.

The Red Devils put Southampton under huge pressure after the interval and Greenwood equalised following great work from the excellent Paul Pogba, who had struck the crossbar in the first half.

A point ensured United is unbeaten in 27 Premier League away matches, matching a record in the English top flight set by Arsenal between April 2003 and September 2004.

James Ward-Prowse tested David de Gea with a well-disguised free-kick in the first minute but United soon got into their stride.

Pogba's header looped up and struck the crossbar, with Anthony Martial's attempt following up cleared off the line by Mohammed Salisu.

Salisu came to the rescue again when he blocked a shot from Pogba, who headed a Luke Shaw free-kick over as Saints continued to look vulnerable from set-pieces.

It was Southampton who were in front on the half-hour mark, though, as Jack Stephens robbed Bruno Fernandes and Adams' left-footed shot from just outside the penalty area struck Fred before flashing beyond De Gea.

The Red Devils were level 10 minutes after the break as Greenwood's scuffed left-footed shot in a crowded box squirmed under Alex McCarthy after Pogba and Fernandes combined to create the opportunity.

Pogba was causing Saints all sorts of problems and he flashed a shot just wide after Jadon Sancho had replaced Martial.

Greenwood nodded wastefully over the bar and McCarthy palmed away a downward header from Fernandes as United dominated.

De Gea produced a sharp reflex save to deny Adam Armstrong against the run of play after Harry Maguire was dispossessed by Ward-Prowse, with Saints' new striker somehow failing to nod home at the back post from the resulting corner.

Jesse Lingard was introduced late on, but Ole Gunnar Solskjaer's side was unable to snatch all three points at a ground where they came from two goals down to win last season.