Thierry Henry says defeat at West Brom is a "massive setback" to Manchester United's top-four chances, but does not think they are out of contention.
United travelled to The Hawthorns on Sunday with renewed optimism after four wins in a row in all competitions.
However, after Juan Mata was sent off in the first half for two quick yellow cards, Salomon Rondon scored the only goal of the game in the 66th minute to secure victory for the hosts.
The defeat means United missed the chance to leapfrog West Ham in the Premier League and Louis van Gaal's side remain three points behind fourth-placed Manchester City having played a game more.
"It is a massive setback," said Henry on Super Sunday. "As you can see, he [Van Gaal] is upset at the sending-off of Juan Mata and the goal they conceded was not because they were down to 10 men, they could have defended that a bit better.
"They had a lot of possession, they arrived here on a high, but they are still in the mix. They played a lot of games and it was always going to be difficult here, but it is a blow."
With nine games of the season to go, Van Gaal said afterwards that United need to take a maximum 27 points to finish in the top four.
But Jamie Carragher does not think the result at The Hawthorns will necessarily be decisive in their season.
"It was always going to be difficult for Man United to go and get that goal and win the game," he said. "I do not think this one result is that big, but they have three cup ties coming now and if that does not go well for them then that is when it will turn back again.
"I think today the sending-off is a massive factor whether we like it or not, and maybe Manchester United could have done more going forward, they have been criticised this season for playing slowly at times.
"But West Brom are the type of team that because they have so many men behind the ball, it is okay saying you want to play quick, but they force you to keep the ball and go sideways as they are such a tight unit.
"Their centre-forwards are on your central midfield players, so it is very difficult to get that pace in your play against West Brom."