Roger's 89th-minute strike rescued a point in a 1-1 draw for Levante as Celta Vigo failed to make their dominance count at Estadio de Balaidos.
Enrique De Lucas got the benefit of a marginal offside call to put his side ahead in the first half, yet despite dominating possession after break the home side could not add to their tally.
Levante made them pay late on as Roger popped up to turn the ball home from close range after fellow substitute Michel had volleyed across the face of goal.
Roger's last-gasp heroics denied Celta back-to-back wins for what would have been the first time this season and they are now three points clear of the relegation zone, while the point keeps Levante comfortably inside the top 10.
Levante started the match well with defender Sergio Ballesteros blasting an effort over the bar after the hosts only half-cleared their lines from a corner.
De Lucas forced a save from Levante goalkeeper Gustavo Munua in the 22nd minute as Celta began to find their feet, while two minutes later the dangerous Obafemi Martins had a chance down the other end but drilled wide.
The breakthrough came on 37 minutes when Iago Aspas' through-ball was collected by De Lucas with the Celta frontman looking narrowly offside, but he did not hesitate and duly tucked the ball beyond the goalkeeper.
Celta looked good value for their lead with Levante restricted to optimistic efforts for much of the second half, Martins and Juanlu both off target from distance.
The hosts should have made it two in the 66th minute when Gustavo Cabral's header from a free-kick drew a superb reaction save from Munua.
Mario Bermejo had the ball in the net for Celta in the 87th minute but the effort was ruled out for offside as the hosts again failed to put the game to bed.
And within moments they were punished to the full when Jose Barkero lofted a pass into the area for Michel to volley across the six-yard box where Roger was on hand to turn the ball home.
Celta might have claimed all the points in the third minute of added time but Angel Rodriguez contrived to head wide from a corner when left all alone six yards from goal.