LEVERKUSEN -- Bayer Leverkusen coach Roger Schmidt has said he is wary of the threat posed by Tottenham and his former player Son Heung-Min in Tuesday's Champions League match.

Schmidt travelled to London to watch Spurs' 2-0 win over Manchester City at White Hart Lane a fortnight ago.

"Tottenham play great football, it's a great atmosphere at White Hart Lane, and they certainly deserved the 2-0 win," he told a news conference.

"You can see they've invested in all aspects of their game, making them very well organised, very aggressive, also in terms of switching play once they have won possession, and very solid defensively. They are very strong opposition.

"Equally, in terms of the Champions League, this is when it really gets going here at the BayArena. This is a stage where we can show what we can do. There is no better chance for us, no better opposition for us to show that against in this group."

Son Heung-Min is in fine form for Tottenham Hotspur. Tottenham Hotspur FC/Tottenham Hotspur FC via Getty Images

Son spent two seasons at Bayer, the latter under Schmidt, before joining Spurs for £22 million last summer.

After struggling with form and fitness in his first season, he has five goals in five starts this term and Schmidt said: "We have to keep an eye on every player. But from seeing the game at White Hart Lane [against City], Son was excellent. We know what he's about.

"He spent a year here with me, and is a great player and a great person as well. After a tricky first year, he is now showing his real potential, and I hope he carries on in that vein. With the possible exception of tomorrow night."

Leverkusen boast an in-form goal-scorer of their own in former Manchester United and Real Madrid forward Javier Hernandez, who has scored seven times in nine appearances this season.

Schmidt believes the 28-year-old Mexican, often a substitute in the Premier League and La Liga, is benefiting from playing full matches in Germany.

"Stats show that when he's had a chance to play, he scores goals," he said.

Schmidt -- whose team have drawn against both Monaco and CSKA Moscow in the Champions League -- said he had yet to make a decision on the availability of Lars Bender against Spurs after the Germany midfielder got flu.