Manchester United captain Bruno Fernandes had a penalty saved as his team slipped to a 3-1 defeat at Brentford in the Premier League on Saturday, putting more pressure on manager Ruben Amorim.
Amorim's side paid the price for another error-strewn display as Igor Thiago netted twice in the opening 20 minutes to punish shambolic defending.
Benjamin Sesko reduced the deficit with his first goal for United before half-time.
United captain Fernandes squandered a golden opportunity to put his team in contention for at least a draw. Fernandes was made to wait several minutes to try to equalise with his penalty, awarded for a clear foul on former Brentford forward Bryan Mbeumo, and his weak effort was easily saved low down by Caoimhin Kelleher.
Brentford wrapped up the game in stoppage time when Mathias Jensen netted with a powerful effort following a quick break.
It was yet another forgettable performance by Amorim's side who were 2-0 down early on.
Thiago rifled a shot into the top corner after being sent clear by Jordan Henderson's pinpoint through ball in the eighth minute and doubled his side's lead from close range after United keeper Altay Bayindir could only push a low cross into his path.
Striker Sesko scored his first goal for the club in the 26th minute, slamming home after his first two efforts were blocked in a goalmouth scramble.
But the visitors never really built any momentum after the break as they suffered their third league loss of the season.
After beating Chelsea last time out, there was hope that United could build on that victory.
But the old failings were there for all to see, especially in defence, and Brentford thoroughly deserved a win that will once again put the spotlight on Amorim's future at Old Trafford.
Defeat left his side 13th in the table with seven points while Brentford moved above them on goal difference.
Fernandes looked crestfallen at the end as he applauded United's visiting fans – his penalty miss the key moment in a game that lacked real quality.
“We didn’t control the game. We played the game of Brentford,” Amorim told TNT Sports. “First balls, second balls, set pieces. All the crucial moments were against us. Tough to lose again but we need to think about the next one.
“The first goal was a long ball. We worked on that in the week, and on set pieces. One touch they had the opportunity. We need to do better.
“We didn't play our game. We only had control for some moments. But it was more or less all the same. We need to play our games, not the opponents, but they were stronger on that.”
The latest loss for United came after previous league defeats to Arsenal and Manchester City, with a humbling League Cup exit at the hands of fourth-tier Grimsby Town also thrown in so far this season.
United failed to build on a win at Chelsea last week and still haven't recorded back-to-back victories under Amorim since his first match in charge in November last year.