The Iron's equaliser didn't come until the final minute but it was well deserved, although Oxford must have felt their efforts deserved maximum reward.
U's goalkeeper Chris Tardif pulled off two fine first-half saves and Leo Roget and Jon Ashton wer key figures in an overworked visiting defence.
Ian Baraclough's point-winning goal was just reward for a tremendous display and Andy Keogh's skills were displayed to full effect as the Iron dominated for almost 80 per cent of the game.
Scunthorpe took control from the start as flowing football came from both flanks and the Oxford defence came under tremendous pressure.
The first real shot on target came after 11 minutes when Peter Beagrie forced Tardif to save at the second attempt.
Richard Hinds, making his home debut, raced forward to drive wide before Beagrie was off target with a 25-yard screamer.
Oxford's rearguard was literally under siege as skipper Andrew Crosby headed over and Baraclough fired point-blank at Tardif.
Keeper Tardif continued to earn his money when he flicked Steve Torpey's superb overhead kick over the bar.
However, for all their pressure Scunthorpe found themselves going behind in the 32nd minute. Oxford marksman Tommy Mooney was fed the ball 25 yards out and he delivered a fine right-foot shot that gave Paul Musselwhite no chance.
Following that the visitors showed a little more resolve up front with Steve Basham and Lee Bradbury getting in testing shots.
The second half opened with Chris Hackett forcing Musselwhite to save and the home keeper then halted Mooney with a brave save at his feet.
Substitute Cleveland Taylor brought life to the Scunthorpe attack late on, but they had to wait until the final minute for a reward.
It came after tremendous pressure, when Crosby lifted the ball low into the box and Baraclough cracked home a vital leveller.