Tom Homer scored 22 points as London Irish gave Worcester a five-try Aviva Premiership Rugby 42-24 beating at the Madejski Stadium.
The full-back converted four of his side's scores, added a couple of penalties and also crossed for one of those touchdowns himself. Centre Steve Shingler, number eight Chris Hala'ufia, wing Adam Thompstone and centre Jonathan Joseph also went over for the Exiles while wings Marcel Garvey (2) and Miles Benjamin touched down for the Warriors.
The Exiles' win was all the more impressive as they were without five injured first-teamers, with Worcester's main absentee being former England scrum-half Shaun Perry - who has a long-term knee problem. Despite their injuries, Irish came out determined and, within eight minutes, they grabbed the first try of the match as hooker David Paice found a gap in the Warriors' midfield just inside the visitors' half and raced through.
Shingler was on his left and took the pass to get over the line from 35 metres out despite the close attentions of the covering defence, who tackled him on the line. Homer converted but Irish found themselves down to 14 men when scrum-half Darren Allinson deliberately held back Benjamin on the Exiles' 10-metre line to earn himself a spell in the sin-bin.
Worcester took advantage as former England fly-half Andy Goode went past the home centres on the left to feed Benjamin for a corner score that the stand-off also converted. However, two mistakes before and after Allinson's return to the action gave Homer easy penalties and, with it, a six point lead at 13-7.
The Exiles tried testing Garvey with the high ball, sending three bombs into the left corner danger area for the former Gloucester flyer - but he was safe under them all. Former Leicester ace Goode was having a vintage half with the ball in hand, causing the London Irish defence all sorts of problems.
One of those saw the stand-off feed number eight Chris Jones for a dash to the line which went to video ref David Grashoff for a verdict - but was ruled out.
The hosts took the initiative again after the break, securing the early territory and possession in the Warriors' 22. And that eventually paid off when Hala'ufia picked up the ball from the base of a scrum to storm over under the posts.
London Irish were getting to grips with their task by now as Worcester gave them the chances to attack. They went well ahead when Joseph ran past the opposition and through a gap in the defence from 20 metres out to get another touchdown.
Garvey hit back with a neat try under the posts which Goode converted. But there was not going to be any dramatic fightback from Worcester when Homer ran over for his side's fourth bonus point try, which he converted himself, just after the hour.
That restored the Exiles' 20-point advantage, and, as both sides ran through their replacements bench, the game stagnated.
Thompstone had a chance for a fifth Irish try but was just nudged into touch when a foot from the line. The wing was rewarded, though, two minutes from the end when the sustained attack he started finished with him rounding the defence on the left to score.
That was the icing on the cake which sent Irish leaping up the league, even though Garvey got a consolation score in the last move of the game.