A controversial last-minute penalty try gave Gloucester an extraordinary win over Worcester at Kingsholm.
Referee David Rose consulted the video official before ruling Warriors' full-back Errie Claasens had deliberately tripped Gloucester winger Jonny May.
Worcester, who were chasing their first league win of 2013, had taken the lead with an interception try by Alex Grove.
The result lifts Gloucester into the top four, but leaves the Warriors in increasing danger of relegation.
Gloucester suffered a blow before the game when captain Mike Tindall, who was due to make his 150th appearance for the club, pulled out with a sore hip suffered in a collision during training.
They were more fortunate when Andy Goode's early penalty attempt for Worcester hit the crossbar, and duly took the lead through a penalty of their own kicked by Rob Cook.
The Gloucester full-back repeated the feat with a simple penalty given for offside on the 22, and the home team nearly stretched their lead when wing Jonny May just failed to touch down Henry Trinder's clever grubber kick into the corner.
Goode got the Warriors on the board with a penalty, but Cook failed to make it three out of three, and despite spending much of the second quarter under severe pressure, and losing blindside flanker Sam Betty to a yellow card for a shoulder charge tackle on Charlie Sharples, the Warriors defence was strong.
Remarkably they went ahead when Fijian centre Josh Matavesi sold Trinder and Darren Dawidiuk a dummy and ran in unopposed. But Gloucester responded immediately when Trinder and May broke down the left and exchanged perfectly timed passes before Trinder touched down.
Worcester conceded two more penalties to go further behind shortly after the restart, but Goode's reply kept them in touch. Worcester went back ahead when Gloucester's attempt to run the ball from their own 22 back-fired, and Alex Grove intercepted a loose pass to score.
A fourth Cook penalty put Gloucester back in front, but with six minutes remaining Goode's replacement Danny Gray kicked a nerveless penalty of his own and the Warriors looked to have hung on before a late break down the left saw the wrong-footed Claassen adjudged to have committed the crucial foul on May.
VIEWS FROM THE DRESSING ROOM
Gloucester director of rugby Nigel Davies said:
"The important thing was we kept battling and kept the effort up until the death, and when you do that you give yourselves a chance.
"When we got the ball wide we made good yardage, and Jonny May is always a threat.
"But the decision [for the penalty try] was a difficult one. It went our way, but I'm just glad we played up to the very end."
Worcester head coach Richard Hill said:
"I'm lost for words, because once again it was a cruel way to lose a game. I've never known a season like it.
"There was certainly cover coming across, so it was not certain that a try was going to be scored even if it was a trip. Errie Claassens is such a lovely man and he's absolutely distraught he's got a red card.
"On the positive side I thought we played some really good rugby, we had really good intent attacking from deep, a nice mixture of running and kicking.
"We'll have to keep fighting and working and if we do we'll get some lucky breaks of our own."
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