Kent eased the tension for Rangers, who were trailing to an early goal from Mirko Ivanic at the intimidating Rajko Mitic Stadium, when his 56th minute shot took a deflection off defender Aleksandar Dragovic to beat Red Star goalkeeper Milan Borjan.
It took the sting out of a spirited display by the Serbian champions as they tried to overturn their 3-0 deficit from the first leg of the last 16 tie at Ibrox last week.
“We got a lucky break and I got a bit of luck in the end for my goal,” admitted Kent. “I wasn’t tempted to pass that one to Alfredo (Morelos)! But I think you create your own luck in football.
"We had a game plan and the boys stuck to it. We always felt the opportunities would come.
“We kept it nice and compact at the back. We knew we’d catch them on the counter attack at times and we managed to do that.”
A stoppage time penalty from Ben Nabouhane gave Red Star a 2-1 win on the night as Rangers progressed 4-2 on aggregate to take their place in Friday’s last eight draw.
"I mentioned the other day that each year we want to progress more than we did the previous year,” added Kent. “That was the goal this year. We’ve managed to do that.
“We’re into the quarter-finals now and we’ve got to have some sort of belief (we can go even further).”