Middlesbrough - Moussa Sissoko has added to the injury worries facing Tottenham manager Mauricio Pochettino ahead of Tuesday's Champions League tie at CSKA Moscow.

Sissoko suffered a concussion during Tottenham's 2-1 success at Middlesbrough in the Premier League on Saturday and appears unlikely to make the trip to Russia.

A win in Moscow is vital for Tottenham after its defeat by AS Monaco in the opening round of fixtures.

Pochettino is already without striker Harry Kane and there are major doubts over Mousa Dembele, Eric Dier and Danny Rose, who were missing at the Riverside as Tottenham maintained its unbeaten run and moved into second place in the Premier League.

While Kane's absence is the biggest blow to Spurs, Heung-Min Son showed at Middlesbrough that the team can turn to him for goals.

He claimed both of Tottenham's goals and has now scored four times in his last three games.

Son started only 13 games under Pochettino last season and was unsettled during the close-season, but is now a vital part of the team.

"It's difficult for all players who come from outside England because the Premier League is the toughest in the world," Pochettino said.

"He's a different person today - he's more mature and knows the league now. He's a nice guy that likes to work hard and, in football, you get paid back if you work hard.

"Harry Kane is a very important player for us, but always we talk about the team and we have a strong squad.

"Harry has an injury, he is important, but so are all 25 players in the squad. We are not happy that Harry is out, but that is football.

"I was very pleased with the first half, but I was a little bit disappointed as we created a lot of chances and we weren't clinical enough in front of goal. That is something we need to work on in the future.

"In the second half, we had a few more chances, but we could not be too open or naive, because the game is not done at 2-0.

"When it was 2-1, we suffered a little bit, but we deserved the victory."