With Spurs 1-0 down after Bryan Mbeumo's opener and pushing for an equaliser, Simons was withdrawn with just over ten minutes remaining and replaced by Mathys Tel.
There were loud boos around the stadium as Simons' number went up on the board, but it was Tel who then scored to get Spurs level five minutes later.
Richarlison put the hosts in front in stoppage time but Matthijs de Ligt headed home a dramatic equaliser in the 96th minute.
"But of course every single time I take a decision to sub a player it’s with one aim. To make the team win or get back into the game or try to see the game out. It’s with only one aim. To try to win the game.
"Mathys did well, great goal, great involvement and in general I think Xavi did a fine game. A positive but also you need a bit of freshness."
Pushed on whether he heard the boos after Simons' withdrawal, Frank added: "I'd just say every single time I make a decision, there's one aim and that is to make the team better."