Erik ten Hag has blasted his Manchester United players for letting a two-goal lead slip in their pre-season friendly with Aston Villa on Saturday.
Man Utd led 2-0 in Perth thanks to Jadon Sancho and a Matty Cash own goal. But they were pegged back after half-time by Leon Bailey and then Calum Chambers equalised in stoppage time after easily winning a header from a corner.
Speaking to reporters after a match that was nearly postponed due to heavy rainfall, Ten Hag asserted that his side need to stop committing so many errors.
"Football is a sport of mistakes and we have to decrease the mistakes," Ten Hag said.
"That’s clear but I have seen a lot of progress in these two weeks. In the first half I saw really good football, really controlling and dominating the game but we have to learn from what happened in the second half.
"It’s not possible that you go 2-0 up and then throw it away. That’s what I just said in the dressing room - a drop of focus is unacceptable but for the season [ahead] I’m happy because now I can tell them it cannot happen."
He added: “We have to get out of the dressing room [at half-time] and back in your plan and your focus and back to your performance and that is what we didn’t do.
"We had a lot of movement behind the defending line and scored two great goals so we were 2-0 up at half-time and then our focus dropped. It can be that the guys are tired but that’s not an excuse. They have to perform and it is what we didn’t do in the second half.
"It was the focus. I don’t want to make excuses about the pitch or weather. No matter what, we have to perform."
Man Utd's perfect pre-season record came to an end with Saturday's draw having beaten Liverpool, Melbourne Victory and Crystal Palace on their tour of Thailand and Australia this month.
They will now jet back to Europe ahead of their final two summer friendlies against Atletico Madrid in Norway and Rayo Vallecano at Old Trafford.