Worcester (10) 15
Fortey, Crook Cons:
London Irish (10) 32
Tagicakibau, Hala'ufia, Hodgson, Danaher, Thompstone Cons:
D Armitage 2 Pens:
Tagicakibau scored the first of London Irish's five tries
London Irish sealed third place in the Premiership with a bonus-point victory over Worcester in the final game of the regular season at Sixways.
The Exiles will meet second-placed Harlequins at The Stoop in the play-offs after the five-try victory.
Sailosi Tagicakibau, Christopher Hala'ufia, Paul Hodgson, Declan Danaher and Adam Thompstone scored for Irish.
Worcester finished second from bottom but safe from the drop as Bristol had already confirmed their relegation.
London Irish went into the game knowing two points were all they needed to reach the play-offs for the first time in three years regardless of what happened to Sale, who secured a bonus-point win at home to Northampton.
But they endured a tense first half and turned around at 10-10 when Worcester hooker Chris Fortey cancelled out Tagicakibau's try.
After the break, though, Irish's ambition was the difference against a Worcester side who are gearing up for a European Challenge Cup semi-final against French outfit Bourgoin next Saturday.
The Exiles, keen to avoid a play-off at Leicester's Walkers Stadium, ran in four tries to seal their visit to the Stoop.
The Harlequins v London Irish play-off is scheduled for 9 May at 1730 BST.
Worcester director of rugby Mike Ruddock:
"At the end of the game the whole back line were either academy players or former academy players.
"There were a few veterans in the front row but it was great that the rest were all young bucks. It was great to see someone like George Crook scoring a try at the end. It was a great moment for him.
"Obviously we are disappointed to lose but London Irish are a very good team. We let our guard down in the second half but, at 10-10 at half-time, I was pleased."
London Irish coach Toby Booth:
"We achieved our minimum standard by qualifying for the Heineken Cup.
"Our three goals were simple. They were try and win the European Challenge Cup, be in the top six at Christmas and the top four at the end.
"So we have achieved two of those three objectives. What are you in this game for? You are in this game not to come second or third, you are in it to win something.
"There is a massive challenge before we get there but we are still in with a chance and that's important.
"The points scored and against column is, I truly believe, the reason why we are here. We scored more points than anyone and conceded more and got more bonus points than anyone.
"I think it would have been unjust if we had not got in there and I just reminded the players of the fact that they have earned their shot."
On playing Quins in the play-offs: "Honours are even between us and I've heard they may move the game to Twickenham, which will be great as we can bring 20,000 fans which will be fantastic.
"That would be quite nice with it being a London derby. We have played them in double-headers before with 50,000 people watching so, whichever way it will be, it will be tough, but I'm just pleased we have a ticket in the lottery at the moment."
Crichton; Fellows, Gear, Grove, Benjamin; Carlisle, Powell (capt); Black, Fortey, Morris, Kitchener, Bowley, Wood, Collins, Talei.
Ruwers, Fortey, Lyons, Abbott, Arr, Crook, Penn.
D Armitage; Thompstone, Richards, Mapusua, Tagickibau; Hewat, Hodgson; Dermody, Coetzee, Skuse; Kennedy, Casey (capt); Danaher, S Armitage, Hala'Ufia.
Corbisiero, Buckland, Johnson, Hudson, Thorpe, Ojo, Catt.