Zlatan Ibrahimovic marked his return from suspension with a 94th-minute penalty to earn Manchester United a 1-1 draw against Everton at Old Trafford on Tuesday.
A deliberate handball by Ashley Williams, who was sent off, allowed Ibrahimovic to cancel out Phil Jagielka's opener and extend United's unbeaten run in the Premier League to 20 matches.
But it remained an unwelcome result for Jose Mourinho's side, who have now drawn nine games at home this season and trail fourth-place Manchester City by four points.
"The performance from a football point of view was not good, but I am very pleased with the effort," said Mourinho, whose team had drawn 0-0 at home to West Bromwich Albion on Saturday.
"It is an amazing run of 20 matches unbeaten, but too many draws at home.
"We don't kill off enough opponents and at the end of this season I think we will be punished by that."
Ibrahimovic's last-gasp spot-kick — his 27th goal of the season — meant United held on to fifth place, three points above Arsenal and Everton having played a game more than the former.
But the Europa League looks increasingly like their best hope of securing a return to the Champions League next season.
They face Belgian side Anderlecht in a two-legged quarterfinal later this month, with the winners of the competition assured of a place at Europe's top table.
United manager Mourinho welcomed top scorer Ibrahimovic and Ander Herrera back from suspension, while Paul Pogba returned to the bench following a hamstring injury.
His side fell behind in the 22nd minute when Williams flicked on Kevin Mirallas's right-wing corner and centre-back Jagielka held off Marcos Rojo to poke a volley between David de Gea's legs.