Ten-man Rangers hold Villarreal to goalless draw at Ibrox
Daniel Candeias was sent off in the first half but the Light Blues held out to draw 0-0.
Ten-man Rangers and Villarreal couldn't be separated as the sides played out a goalless draw at Ibrox.
Light Blues goalkeeper Allan McGregor was in inspired form on the night, making a series of stunning saves to deny the La Liga big-spenders after Daniel Candeias was dismissed.
The result leaves Rangers third in Group G, but knowing victory over Rapid Vienna in the final group match would see them through to the knockout rounds.
Villarreal looked the more likely to open the scoring in the first half but McGregor thwarted their attempts impressively.
The Rangers keeper denied Toko Ekambi twice in quick succession with point-blank stops after the Cameroonian had burst through clean on goal.
Scott Arfield had the chance to edge Steven Gerrard's side in-front but his effort from close-range was directed straight at the visiting goalkeeper.
The first half ended in controversy when Rangers winger Candeias was dismissed.
The Portuguese winger received his second booking just before the interval after he and Morelos sandwiched Caseres, with Candeias eventually receiving his marching orders after a discussion between the officials.
After the break, Villarreal continued to press for a winner which would have sealed their progress.
But Rangers managed to keep out their advances, thanks to a combination of last-ditch defending and McGregor's form in between the sticks.
Kyle Lafferty replaced Alfredo Morelos in attack for the closing stages and breathed fresh life into the home side.
Rangers thought they had won it late on when Glenn Middleton found the net but the teenager's effort was ruled out for offside.