One of few positives for Jose Mourinho was the return of Reguilon after over a month out; the left-back one of his best performers since arriving in the summer.
Reguilon's display, along with half-time substitute Gareth Bale, saw Spurs produce arguably their best football for a number of weeks but ultimately failed to find an equaliser.
"When he was playing he was fantastic," Redknapp told Sky Sports. "He had great energy, was crossing the ball, good in one-on-one situations - he had it all.
"It is no surprise that their performances have not been as good since he has not been playing because he offers so much to this team, and Jose will be delighted to have him back."
Micah Richards, fellow Sky Sports pundit, added: "With Reguilon, it is just the way that he attacks the space, for me. As a full-back, nowadays, you always like to see them going forward.
"He is quick, always plays one-two's, so they will be happy to have him back in the squad."
Tottenham face the return leg of their Europa League last-32 tie with Wolfsberger on Wednesday before games against relegation candidates Burnley, Fulham and Crystal Palace.