Manchester United slumped to yet another Premier League defeat on Saturday after a slow start saw them beaten 3-1 away to Brentford.

Two goals from striker Igor Thiago inside the first 20 minites saw Brentford take a commanding lead. Benjamin Sesko halved the deficit with a strike shortly after.

However, United could not find a way back. Their best chance came from a Bruno Fernandes penalty on 76 minutes, but the United captain was made to wait for a lengthy period as the VAR weighed up whether to send off Nathan Collins and saw his effort saved by goalkeeper Caoimhín Kelleher.

Mathias Jensen netted a superb strike in the game's final moments to secure a 3-1 win.

The defeat means Amorim has now lost 17 of his 33 league games during his spell at United.

Meanwhile, Brentford had won only once in the Premier League and started the day just outside the bottom three, but an excellent team performances was typified by the excellent Jordan Henderson and Mikkel Damsgaard in midfield and Thiago's clinical finishing.

Diogo Dalot, Manuel Ugarte and Matheus Cunha returned after United's win over Chelsea with boss Ruben Amorim's hand forced by injury and suspension.

Noussair Mazraoui was injured, Casemiro ruled out by his Chelsea red card, and Amad Diallo unavailable due to a family bereavement.

It meant summer signings Cunha, Mbeumo -- who received a warm reception on his Brentford return -- and Sesko lined up in the United attack for the first time.

Brentford profited from the first main action after eight minutes as Cunha went to ground and Henderson spotted Thiago's run.

Thiago advanced to crash a shot high off the post past Altay Bayindir, and the subsequent VAR check showed the Brazilian had been played onside by Harry Maguire's back foot.

Cunha drove wide from 20 yards as United sought to recover from the early setback.

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But Bayindir had to make two fine stops in the space of a minute, palming out Sepp van den Berg's point-blank effort and acrobatically tipping over a Collins header after Henderson had found space.

Brentford were swarming all over United and doubled their lead after 20 minutes.

Maguire played Kevin Schade onside this time and Bayindir could only divert his cross into the path of Thiago, who squeezed the ball over the line despite the desperate effort of the United goalkeeper to salvage the situation.

Sesko fired straight at Kelleher, but the Slovenian striker did not have to wait long to open his United account.

Mbeumo competed with Kelleher under Patrick Dorgu's cross and the ball fell kindly for Sesko.

Kelleher kept out two attempts -- a header and a stabbed shot -- but Sesko slammed home at the third attempt and the goal stood after VAR had checked Mbeumo's challenge on the goalkeeper.

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Cunha's low drive was collected comfortably, but the second half was a more sedate affair until Schade got the better of Dalot and Dango Ouattara was denied by Bayindir.

United's frustration grew after Collins was spared a red card, despite not appearing to try and play the ball when holding back Mbeumo, and Fernandes missed from the spot.

Jensen's thunderous drive finally saw off United as jubilant Brentford fans directed cries of "you're getting sacked in the morning" at Amorim.

Information from PA contributed to this report.