Both North-East enemies drew 1-1 at St Jame's Park on Sunday.
It looked set to be enough, but Aleksandar Mitrovic grabbed an equaliser with seven minutes remaining to ensure Benitez - who replaced axed Steve McClaren earlier this month - did not lose his first home match in charge.
Colback, who began his career at Sunderland, has opened up on what message the veteran Spanish manager delivered to his troops during the break.
“He [Benitez] just said we had to be positive and keep going,” Colback explained to The Chronicle.
“It’s a massive point in the end,” he added. “You’re hoping to get the win, but once you go 1-0 down, to get a point is a good result in the end.
“I think it was cagey. Neither side wanted to give anything away or lose the game knowing how important it was."
A good result all things considered for Newcastle, but Benitez's side remain in the relegation zone, three points behind 17th-placed Norwich City - albeit with a game in hand.
United, in 19th, also sit one point behind Sunderland, with both sides having eight games in which to preserve their top-flight status.