LONDON — Tottenham Hotspur manager Mauricio Pochettino said he was living the dream in the build-up to their Champions League semifinal against Ajax Amsterdam but it must have felt like a nightmare at times against the classy Dutch side on Tuesday.

His patched-up team were comprehensively outplayed in the first 30 minutes and were fortunate to only concede a 15th minute goal that was coolly converted by Donny van de Beek to give the visitors a 1-0 win and a precious away strike.

With forwards Harry Kane and Son Heung-min unavailable through injury and suspension respectively, Spurs were blunt in attack and they also lacked creativity in midfield as they slumped to their 18th defeat of the season in all competitions.

To make matters worse Jan Vertonghen, one of three center backs employed by Pochettino, had to be substituted in the first half after a sickening collision with team mate Toby Alderweireld left him with concussion and a bloody nose.

"The attitude was there but we didn't find a way to play," said Pochettino, who has led Tottenham to their first semi-final in Europe's blue-riband club competition for 57 years.

"We didn't show the energy that we wanted to show. They showed more energy than us. The way we conceded the goal was painful. They were more proactive than us.

"Our approach to the game was not good. I am the manager so I have responsibility."

Despite an improved second-half display, Spurs managed only one effort on target as they lost at their new stadium for the second time in four days and there is a suspicion that they are running on empty at the end of a demanding season.

Tottenham face a crucial trip to Bournemouth in the Premier League this weekend as they seek to secure a top-four finish to guarantee qualification for next season's Champions League.

After that they must go to Amsterdam where they will bid to become only the second side to reach the final having lost the first leg at home -- after Ajax managed the feat in 1996.

Pochettino, however, remains hopeful that his side can turn things around next week when his prolific South Korean striker Son will be available again after his suspension.

"We pushed them to play deeper (in the second half). We started to press in the way we wanted to press. The second half has given us the hope for the second leg," he said.

The Argentine coach was also asked to clarify the situation with former Ajax defender Vertonghen, who needed lengthy treatment to stem the bleeding from a gash on his nose before it appeared he was ready to go back on and continue playing.

The clearly-groggy Belgian international was then helped off the field as it became clear he could not continue.

"I wasn't involved. It was the doctor's decision. It is so important," Pochettino said. "The rules and the protocol were there and the medical staff followed them.

"In the next action we had to take him out. The most important thing is the health of the player. I am never going to be involved. I only need to listen and hear what they say and take a decision. I will never debate their decision."

Meanwhile, Ajax coach Erik ten Hag praised his young lions after the Dutch club moved within touching distance of the Champions League final.

"A fantastic achievement. We fought like lions," Ten Hag said. "We are halfway there and in good shape. The willpower was very nice to see."

Having beaten holders Real Madrid and fellow European giants Juventus on the way to their first Champions League semi-final since 1997, Ajax again showed why so many of their squad are attracting attention from some of the continent's biggest clubs.

Van de Beek was superb and even overshadowed Barcelona-bound fellow midfielder Frenkie de Jong, while 19-year-old captain Matthijs de Ligt showed maturity beyond his years to marshall the defense as Tottenham improved after the break.

Had David Neres not been denied by the post late on Ajax's position would look impregnable, but Ten Hag knows the job is not yet completed.

"I think it's an excellent result for us. We won the game. We are satisfied. We have a very good starting point, but we're only halfway through," he told reporters.

"We can play football in different styles. We can defend very well. We have a team that works together really well; they can fight together really well."

The 22-year-old Van de Beek said he still expected a tough battle next week in the Johan Cruyff stadium.

"The first 30 minutes were good but we found it tough after that. They changed things up and we had difficulty dealing with that," he said. "The second half was really a battle.

"It will be a tough game next week in the Arena, but with our own supporters behind us it will certainly be a huge boost to reach the final. We have to develop a good tactical plan so we can play like we did in the first 30 minutes this evening." — Reuters