Tottenham captain Son Heung-min believes his side's 1-0 defeat to AZ in the first leg of their Europa League last-16 tie should come as "a big wake-up call".

Lucas Bergvall's own goal proved to be the difference between the sides as a poor Spurs registered just a single shot on target during their trip to Alkmaar.

Only in defeat to Liverpool last month have Tottenham registered fewer shots on target this season.

"It's nowhere near where we should perform," Son told TNT Sports after the game. 

"It was very disappointing that we performed like this, including me." 

Tottenham's hopes of winning silverware this season will be over if they do not overturn the deficit in the second leg in London next Thursday. 

"It's a big wake-up call because next week is the biggest game of the season," the Spurs skipper said. 

"Everyone is very disappointed about the individual performance and the team performance. We have to look at ourselves.

"There are no excuses, we were not good enough. It's just 1-0, it's still not finished, and next week we have to be much better."

Spurs boss Ange Postecoglou also echoed the captain's sentiments. 

 "It was not a great night for us. Obviously, it's a disappointing result but a really disappointing performance," he said. 

"We never got a grip on the game, never really got control at any stage. We were always struggling both on and off the ball. But it's only halfway and we're still in the tie."

To make matters worse for the Premier League side, they will be without Rodrigo Bentancur for the home leg after the midfielder picked up a third booking of the season.

"We were always running the tightrope with him being on the yellow cards. It's disappointing to lose him for the second leg, but we have seven days to address that," said Postecoglou. 

Dominic Solanke, meanwhile, lasted only 20 minutes on his return after seven weeks out, taking a blow in stoppage time.

"I think it was a knock, hopefully it's nothing too bad," the Spurs boss said of Solanke's injury.