The two teams meet for the first time since last season’s Europa League final in May, in which Spurs triumphed 1-0 thanks to a Brennan Johnson goal.
Following their bitter 1-0 defeat to rivals Chelsea in the Premier League last weekend, Frank will aim to bounce back against a United side who went unbeaten last month, with manager Ruben Amorim winning manager of the month.
Team news
Frank firstly spoke on team news, including vital updates on Cristian Romero and Dominic Solanke.
“Yes, everyone came through (the game) well. The ones that had been out for a small spell, Cuti (Romero) and Dest (Udogie), responded well. Kudus is touch and go for tomorrow.”
On Solanke: “I think the international break will be the big decider and we have two weeks to push him for the next steps. It is going forward. It was clear he was not ready before the international break. After is what we’re aiming for and you always want to get it right.”
Scarlett needs games to improve as a young player
Questions next turned to academy product Dane Scarlett who was recently training with the England squad under Thomas Tuchel.
“I think he is a fantastic finisher. His finishing is at a very high level and probably he needs what every player needs and to play games.
"That is the biggest thing and right now the competition is tough here. It's difficult to give him four or five games in a row. It's not impossible but it's difficult. He needs to play games.”
Muani is not ready for 90 minutes
Frank next touched upon Randal Kolo Muani who earned a recall from France national team boss Didier Deschamps after a run of impressive form in North London.
(He needs) sharpness because fitness wise he is fit to start and play, but to do it at the highest possible intensity throughout the 90 mins, I don’t think he is there yet. But I think it was a very promising game against Copenhagen and I think he is on the right track.
“I think he has a little bit, Solanke is also good to run in behind, but that pace to go on outside. I like his combination play, link-up play and I just think he’s a good player.”
United will be a tough test
Next, the media turned to this weekend's opponents in Manchester United and what threat they will cause against Frank's side which has been poked full of injuries in recent weeks.
"It is a United team with more confidence. I think Ruben and his coaching staff have done a good job. It has obviously been a tough year for them so I admire him a lot. They are in a moment where they have every key player available. We know exactly what to expect from them. They have an incredibly dangerous front three.
"No, I'm not surprised (how well Bryan Mbeumo is doing). When you work with someone for six years, you get to know them. For me, I think he has been their best offensive player. He is the perfect example of a front player in terms of attitude. Not for tomorrow, but I wish him all the best."
Frank speaks on becoming Spurs boss
Finally, Frank opened up on becoming Tottenham manager and start to life in North London as he turned around a side who were close to relegation last season.
"When I walked in here... 'Is it different (to Brentford)?' No, it is the same in many ways. A lot is exactly the same, it is just different people, tactics. When I say learning curve, learning about reactions, learning about people."
"We all have egos. If you don't have an ego, we would not be sitting here. Some are better managing it themselves. Some need a bit more guidance managing it.
"It has been super exciting. A big learning curve. You learn every single day. I think it has been overall fine. I think we have done quite well to get the amount of points we have done in the Champions League and Premier League, competing on both fronts. We are far from where I want us to be but we will get there."