Spurs won 4-0, through goals from Brennan Johnson, Wilson Odobert, Micky van de Ven and Joao Palhinha. Johnson was also sent off in the second-half.
Frank said afterwards: "I think it was a step forward. I liked what I saw from Brennan, it was classic Brennan, running in behind. And I really liked the assist from Xavi (Simons). Very good assist from Xavi. So happy that it was a goal from Brennan, assist from Xavi. I liked bits from Wilson, and also of course he scored.
"I think (Randal) Kolo (Muani) looked like a handful, in many situations he could easily have scored one or two goals maybe in the end. But I think all of them have much more to come. But it was definitely a step forward."
On Kolo Muani, he continued: "I think he's just taking steps in the right direction and he's getting more and more fit. And I will still go as far as I don't think he's fully firing yet. But you can see he's such a handful to play against.
"The goal is a ball in behind where he just can't really control it, the defender and he's practically on the goalkeeper. And then he shows extreme composure to just take the ball down and a nice assist for Wilson.
"And he's through two or three times and could have scored more. So I think he was a threat. Probably also should have scored on the header."
Frank added, "I definitely didn't expect us to win 4-0 in a game like this. I expected it to be difficult. A combination of I know Copenhagen is a difficult opponent, also in Europe and on the pitch. I know it's even more difficult in the park, of course. And it's clear that our offensive game hasn't been super explosive. So that combination could have been tricky, but luckily it went the right way for us."