Manchester United defender Lisandro Martinez believes they must be more ruthless.

The Red Devils fell to a late defeat to Arsenal in the Premier League on Sunday.

United were beaten 3-2 at the Emirates Stadium, with Arsenal's winner coming in the 90th minute.

“For sure we are disappointed," Martinez said in an interview with MUTV.

“We want to win the game, but we didn't, and we are very disappointed.

“But we are strong, we have to keep fighting and we go for the next one."

"I think we can win the game today," he added.

“But this is about details. If you are not [focused on] every detail, you can't win.

“We have to be strong, and we have to learn also from every experience. [It] cannot happen again, for sure it cannot happen again.

“We have to be really focused on the game and we have to kill the game. We have to win."