It's crystal clear, Red Devils are powerless

Lisandaro Martinez (left) and Diago Dalot of Manchester United. [AFP]

Manchester United slumped to another meek home defeat as Crystal Palace won 2-0 at Old Trafford on Sunday, while Tottenham eased the pressure on Ange Postecoglou by beating Brentford 2-0.

Jean Philippe-Mateta was Palace's hero with both goals in the second half as United suffered a fifth defeat in their last six home league games.

Victory takes the Eagles above the Red Devils in the table as Oliver Glasner's side climb to 12th.

Three consecutive wins for United had lifted the mood around Old Trafford, but it was back to square one for Ruben Amorim after another home display lacking in creativity and riddled with defensive lapses.

Amorim's decision to start without a natural striker backfired with both Rasmus Hojlund and Joshua Zirkzee left on the bench.

Midfielder Kobbie Mainoo started in a centre-forward role after scoring in a 2-0 victory over Romanian side FCSB in midweek.

The England international's scuffed strike came back off the post in United's best effort of a bright opening before their attacking threat fizzled out.

Palace have lost just one of their last seven league games to recover from a miserable start to the season.

The visitors missed the creative spark offered by Eberechi Eze for the first hour as an injury meant he was only fit enough for a cameo appearance off the bench.

But Eze made an instant impact as from his free-kick Maxence Lacroix's header came back off the bar and into Mateta's path to fire home.

Worse was to follow for United as Lisandro Martinez had to be stretchered off with what appeared a serious knee injury.

Palace showed no mercy to secure the three points when Daniel Munoz charged through the middle of the home side's defence and unselfishly squared for Mateta to knock in his sixth goal in five games.

Meanwhile, Spurs eased fears they could be dragged into a relegation battle as Postecoglou's injury-ravaged side kept a rare clean sheet to see off Brentford.

The Bees were left to rue a number of missed chances against Tottenham's makeshift defence with Micky van de Ven and Cristian Romero again absent.

Brentford also lent the visitors a helping hand with the opening goal.

Hakon Valdimarsson flapped at Son Heung-min's corner and Vitaly Janelt headed into his own net on 29 minutes.

Yoane Wissa's header came off the bar as Brentford pushed for an equaliser.

But Spurs picked them off on the counter-attack when Pape Sarr prodded through Valdimarsson's legs from Son's pass.