Mauricio Pochettino has said Tottenham Hotspur need to sign players and are aiming to do so in January despite making their best ever start to a Premier League season without new faces.

Spurs failed to add a single player during the summer window -- a first for a Premier League club -- but have collected 21 points from their opening nine fixtures.

But speaking after Saturday's 1-0 victory at West Ham, Pochettino said: "In football you always need to think you can improve, and you need to try to improve your squad.

"I've tried to explain before what happened in the summer, the circumstances. But if you say to me we were so clever and are geniuses because we didn't sign [anyone], and now after nine games it's the best ever start in the Premier League, I'm not going to be the kind of person to say: 'Yes, we are geniuses.'

"We couldn't sign for different circumstances, but we wanted to sign. I think it's maybe a coincidence, or we worked a lot, or because we're clever, but to be honest always you try to sign.

"Now January will come and we're going to try to sign. I think it's not only us -- all the clubs and managers want to sign players, must refresh the squad.

"We need to try again in January or the summer if we want to move on the team and the club."

Spurs' winner at West Ham came when a Moussa Sissoko was converted by Erik Lamela and Sissoko, who has struggled to win over the Spurs fans since arriving from Newcastle, got a standing ovation when he was substituted in the second half.

"I think he's a very honest, professional player," Pochettino said. "You know what you're going to receive from him. In a squad of 25 players, you always need different types of players and I think Moussa provides the team with a very good balance.

"I'm happy that the fans are starting to see him as a player who helps the team and helps the club, and recognise his value."

Lamela, who missed more than a year until last November after operations on both hips, has now scored five goals in seven games.

"The most important thing is when you feel the trust and confidence," Pochettino said. "We believe in him, we trust in him.

"I think he's more mature. That's the key, and he's more relaxed and calm in front of goal. Now he needs to be consistent and play at his best, and [we need] to manage him in the best way.

"He's had a lot of injuries in his five and a half years here. The season before last was tough for him, but [you need to show] patience, belief, care about your player."