Tottenham boss Mauricio Pochettino accepts his side have some hard work to do to cure their defensive woes after shipping a two-goal lead in the Champions League at Olympiacos.

Spurs, who reached last season's final, looked on course to open this term's campaign with a win in Greece after Harry Kane and Lucas Moura struck in the space of four first-half minutes to put them in command.

But just over a fortnight after letting a similar advantage slip against Arsenal, they again capitulated as goals from Daniel Podence and Mathieu Valbuena earned the Greek side a deserved 2-2 draw.

Tottenham's season so far has been beset by an uncharacteristic weakness in defence and Pochettino is determined to put that right.

"In the beginning of this season we are conceding a lot of chances and lots of goals and we need to change that," the Argentinian said. "The only way we can change is being more demanding from ourselves.

"And that is the way we are going to approach the different days and be more consistent.

"Training needs to be harder. Psychologically harder.

"I feel very disappointed, in the first half I wasn't happy with our performance, from the beginning we had a plan and we didn't respect the plan, that is what disappointed me most and that is what I told the players at half-time.

"We scored two goals in my opinion, from the penalty and a good goal from Lucas, but if you only analyse the performance it wasn't great, we conceded a lot of chances to Olympiacos, the way we conceded the first goal was so painful."

Spurs looked back to their best against Crystal Palace on Saturday, but they were unable to reproduce that in one of Europe's most hostile atmospheres.

They endured a torrid opening 20 minutes and could have been behind by the time Kane smashed home his 15th Champions League goal in 20 games from the spot.

Moura's powerful drive from the edge of the area put Spurs in control before Podence's goal on the stroke of half-time allowed Olympiacos back into it.

Valbuena completed the comeback with a 53rd-minute penalty, to leave Spurs licking their wounds.

"We didn't translate from Saturday that aggressiveness that this level of game demands and that is my biggest disappointment," Pochettino added.

"It's everyone's responsibility and it's not possible for, in three days, how we start the game today to be a massive difference. That is my disappointment. I feel disappointed for everyone.

"At half-time we realised it and changed it and in the second half we were a little bit better and we conceded a very soft penalty.

"We created many chances to score, we dominated the second half. Overall, I thought the result was fair."

Olympiacos coach Pedro Martins was happy his side were able to come back from a sticky situation, but was left wanting more.

He said: "We dominated the game. We had more chances, but we paid for two mistakes. We reacted well after that.

"Our reaction was more than positive and we were better.

"Tomorrow critics will say Tottenham didn't play very well, but Olympiacos did play well.

"The draw is good because we came back from 2-0 but at the end we could do better."