Oxford Untied maintained their third division play-off challenge by winning a stormy Gay Meadow encounter by the odd goal in three.
Both sides were reduced to ten men in the second half - with Oxford forced to play the entire second half with defender Scott McNiven in goal, after Andy Woodman was stretchered off with a nasty facial injury during first half stoppage time.
Woodman was hurt in the scramble that resulted in Shrewsbury's Welsh under-21 midfielder Jamie Tolley levelling the scores.
Tolley's equaliser cancelled out Dave Waterman's 20th minute opener for Oxford - who ultimately secured victory just 40 seconds into the second half when substitute Jefferson Louis broke clear of the static Shrewsbury defence to put the visitors back in front.
On the hour Shrewsbury's leading scorer Luke Rodgers was red-carded for a lunge at Oxford defender Matt Bound with Ian Atkins' side having to play the closing stages of the game also with ten men, after midfield man Bob Ford was dismissed for a second bookable offence.
Improving Shrewsbury, who went into the match unbeaten in their last five games, started brightly, but were rocked on 20 minutes when Woodman netted from close range after the home defence failed to clear an in-swinging corner.
With former Shrewsbury striker Lee Steele creating a number of good openings for Oxford, they often seemed likely to increase their advantage - but were pegged back deep into first half injury time.
Woodman parried a stinging shot from Shrewsbury winger Sam Aiston and in the ensuring melee Tolley forced the ball into the net - with Woodman appearing to collide with one of his own defenders, receiving a sickening blow to the head in the process.
But within a minute of the restart Oxford regained the lead as Louis pounced on some hesitant defending to lift the ball over advancing Shrewsbury keeper Mark Cartwright and despite having a rookie in goal, the visitors safely protected their advantage to earn a vital victory.