The reaction Frank got from the Tottenham supporters was a major contrast to the standing ovation he received from the Brentford faithful when he stepped on to the pitch before the match.
The Dane spent seven years in charge of the Bees before making the switch to Spurs and was asked if he was enjoying the challenge.
“When you need to put in a big, big shift and it’s not smooth and it’s tough, it’s probably difficult to enjoy it,” said Frank.
“If I run hard, I don’t enjoy that moment, but I know I need to keep my head down and run hard to get through it to get my fitness up, or win a race, or whatever.
“We are in a situation where you need to run hard, to stay in it, to get through it.
“On the other side, when we look back on this spell or maybe this first year when it was tough, you’ll think what a learning, what an experience, it made us so much better for the future.”
Spurs have kept seven clean sheets under Frank in the Premier League this season, having only picked up six in 2024-25 with Ange Postecoglou in charge, and there are clear signs of recovery.
They won 1-0 at Crystal Palace prior to the Brentford trip.
Frank accepts there are still further areas for improvement but insists there are plenty of reasons to be positive.
“It’s not perfect, we want to be a free-flow team,” Frank said.
“A few things I went to reinforce positively is our last two away performances. The foundation we were building was very strong and we were very strong defensively. That is hugely important and we understood how to close down their transitions.
“We are working very hard on the offensive part of the game.
“Football is a game of mistakes. You lose the ball, that happens – but if half of those can be better, it will provide more attacks.”
Frank was unable to call on several key figures on Thursday as he continues to contend with a lengthy absentee list.
James Maddison, Dominic Solanke and Dejan Kulusevski are among those on the sidelines with injuries, while Xavi Simons is serving a suspension.
“Expectation is good and I also think we are probably in a bit of a transition,” Frank said.
“Not that we don’t want to play a lot better, but the club, the squad, the injuries, all that taken into consideration is part of that.”
Tottenham return to action on Sunday when Sunderland visit north London at 15:00 GMT.