The hosts immediately came out on the front foot, but the Hammers broke forward when they could and had the first big opportunity, as Aaron Wan-Bissaka pulled the ball back for Mateus Fernandes to hit a first-time shot that Casemiro deflected behind.
Jean-Clair Todibo and Bruno Fernandes then had an attempt blocked at either end, before Casemiro got himself in the way again to deny Jarrod Bowen, and El Hadji Malick Diouf scuffed his attempt harmlessly wide.
Alphonse Areola was forced into the game’s first save in the 25th minute, when he tipped over a looped Bryan Mbeumo effort that looked destined for the top corner.
The Hammers just about survived moments later, as Wan-Bissaka cleared Joshua Zirkzee’s attempt off the line, Todibo blocked Matheus Cunha’s overhead kick, and Bruno Fernandes fired agonisingly wide.
The hosts continued to build momentum, although Konstantinos Mavropanos and Todibo denied Cunha and Bruno Fernandes, respectively, before Bowen danced his way into the Man United box but saw his shot saved by Senne Lammens.
Mbeumo had two promising openings early in the second half, yet Freddie Potts made a vital challenge to deny the winger, and Tomas Soucek stood firm when he did get a shot off, before Luke Shaw blazed his shot over.
Soungoutou Magassa then hit the side netting at the other end, but Man United made the breakthrough just before the hour mark when Casemiro’s attempt was deflected to Diogo Dalot, who stayed calm to convert.
Casemiro was on hand again to stop a Potts effort, before Mavropanos was in position to deflect Cunha’s shot over.
Andy Irving came on as part of a double change and immediately took a corner that saw Bowen’s flick cleared off the line by Noussair Mazraoui, but Magassa was perfectly placed to score his first West Ham goal to equalise in the 84th minute.
Debutant Mohamadou Kante blazed his wide and Bruno Fernandes struck off-target twice late on, as the Hammers recorded the second draw from their last three, which keeps them in the relegation zone.
Man United’s third draw from their last five league games leaves them eighth.
Flashscore Man of the Match: Soungoutou Magassa (West Ham)
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