Ange Postecoglou accepts lacklustre Tottenham were "nowhere near" the level required after they lost 1-0 at AZ Alkmaar in the first leg of their Europa League last-16 tie.

A comical own goal by Lucas Bergvall in the 18th minute gave AZ their first win over an English club in 12 attempts.

Bergvall tried to clear Troy Parrott's shot but only contrived to slice the ball up and over Djed Spence on the goal line.

Despite eight days to prepare for this crucial fixture, Spurs failed to produce an adequate response and did not register a shot on target until the 88th minute.

"We'll analyse it and have a look at the areas where we struggled with, but it's fair to say it was nowhere near the level it needed to be," Postecoglou said.

"I don't think it's a matter of effort or attitude. I don't think it is going out there and not trying, but, like I said, we didn't really come to grips and have the right mindset to tackle an away fixture in Europe.

"You are going to face some pressure when you play away from home in Europe and weather the storm and get to grips with it, but we never really did so that was a disappointment."

But Postecoglou, who has faced pressure following a difficult winter in which Spurs battled a huge injury crisis and slipped to 13th in the Premier League table, believes they can turn things around at home.

"I don't have any doubt about our ability to break them down, but obviously we have to play a little bit differently to how we did tonight, not just with the ball, but without the ball too.

"If we address those things I'm sure we'll be in a position to at least cause them more problems that we did tonight. It's only 1-0 so I guess that's a positive in that we didn't let the game get away from us."

Under-pressure Manchester United boss Ruben Amorim felt his side were "really, really tired" in the final half hour of their 1-1 last-16 first-leg draw at Real Sociedad.

After Joshua Zirkzee had put United ahead just before the hour mark, the hosts replied through a 70th-minute Mikel Oyarzabal penalty awarded for a handball by Bruno Fernandes.

Amorim, whose side host Arsenal in the Premier League on Sunday before next Thursday's second leg, told TNT Sports: "I felt until the penalty we had the control of the game, and then I think the penalty changed a little bit the momentum.

"I felt our team in the last 30 minutes were really, really tired, and you can feel that in the game. So we take this to Old Trafford.

"It is going to be a different game, the pressure is going to be on us in that stadium, and we have to be ready. I think the key will be surviving physically to Sunday and to be ready and fresh for Thursday."