Gloucester maintained their hopes of securing an end of season Aviva Premiership play-off place as a last-gasp red card for Errie Claassens and a penalty try handed the Cherry and Whites an unlikely win.
In the last play of the game and trailing by a solitary point, Gloucester wing Jonny May was tripped by Worcester full-back Claassens with the line beckoning and on the recommendation of the television official, a penalty try was awarded.
And to rub salt in the wound, Cook kicked the extras to give Gloucester a crucial win.
It was harsh on Worcester who for so long looked as though they would sneak a win at their local rivals and end a four-game losing run in the Aviva Premiership.
Despite dominating the game throughout, Gloucester twice gifted Worcester scores with needless errors as Josh Matavesi and Alex Grove darted over for the visitors.
But 14 points from the boot of Rob Cook steadied the ship and allowed Gloucester to improve an unwanted recent record of just win in their last four Aviva Premiership fixtures.
Gloucester dominated the opening 40 minutes, playing all of the rugby in Worcester’s half but their greater territory and try scoring opportunities were not reflected at the break.
Worcester had the first shot at goal on three minutes but the normally reliable Andy Goode fluffed his effort at goal as the Warriors attempted to end their four-game Aviva Premiership losing streak.
Last week at London Wasps, Gloucester scored four tries but were wasteful with their place kicking and eventually slipped to a narrow loss to their play-off rivals.
Missing Freddie Burns through injury, full-back Cook ensured there was to be no repeat performance in front of goal, kicking two penalties inside two minutes to hand Gloucester a 6-0 lead.
Worcester were their worst enemy in the opening 40 minutes, giving away countless penalties with their poor discipline at the breakdown.
But it was Gloucester who were next to infringe on 16 minutes as Goode reduced the arrears with a penalty of his own.
Such was Gloucester’s dominance it was no surprise when Cook was handed another kick at goal but this time the Cherry and White missed his shot at goal.
Referee David Rose warned Worcester about their ill-discipline at the breakdown and it was Sam Betty who was eventually yellow carded on 29 minutes for a high tackle.
A man down it seemed almost inevitable Gloucester would add to their score in Betty’s absence but against the run of play it was Worcester who crossed the try line.
Henry Trinder came galloping out of the Gloucester line to confront Matavesi but the Worcester centre stepped the Cherry and White before galloping clear to score under the posts, with Goode adding the extras with five minutes of the half remaining.
It took Gloucester just three minutes to respond though, Cook cleaned up a poor pass in his own 22, set Trinder free who in turn picked out the free running May.
The angle of the Gloucester winger’s run saw him suck in Worcester’s runners and send Trinder clear for a run under the posts, which was converted by Cook.
With Goode hobbling, Chris Pennell had the opportunity to level the scores at the break but the Worcester winger missed his kick at goal.
It could and probably should have been so much better for Gloucester in the opening 40 minutes but Sione Kalamafoni and Dan Murphy both wasted golden opportunities to cross the Worcester try line.
Worcester started the second half as they had finished the first, with poor discipline handing Gloucester opportunities to extend their lead.
Cook extended Gloucester’s lead just 60 seconds after the break and two minutes later it was 19-10 as Ryan Mills this time kicked a penalty for the home side.
Despite practically playing on one leg after a first-half collision with Kalamafoni, Goode ensured Worcester stayed in touch with a penalty of his own five minutes into the second-half.
Worcester should have been back to within three points after 55 minutes but Goode took the strange decision to go for a crossfield kick in favour of a shot at goal from in front of the posts after Tom Savage had been penalised for getting caught on the wrong side.
Gloucester continued to play brainless rugby in the last quarter and after Goode missed a penalty on 59 minutes, the Cherry and Whites opted to run from their 22 and force the pass.
Grove spotted the pass and intercepted to run through and score near enough under the Gloucester posts against the run of play – Goode converting to make it 20-19 to the visitors.
Worcester boss Richard Hill must have been pulling his hair out with ten minutes remaining as a mistake by Blair Cowan, he was penalised for holding on, allowed Cook an easy kick in front of goal to give Gloucester back the lead.
Rupert Harden was the next man to be penalised at the breakdown as the momentum continued to swing both ways, with Worcester retaking the lead with just six minutes remaining as Danny Gray slotted over a penalty to make it 23-22 to the visitors.
It looked as though Gray’s penalty would be enough to win the game; that was until the last-gasp penalty try awarded to Gloucester after the final whistle had been blown for Claassens’ trip on May, with Cook adding the extras.