Tom Litchfield starred as Northampton powered into the English Prem final with a 45-31 win against Leicester at Franklin's Gardens on Friday.
Litchfield scored a first-half hat-trick of tries, George Furbank crossed twice and Tommy Freeman and Archie McParland also touched down for Saints.
Leicester's Ollie Hassell-Collins crossed over twice in a pulsating play-off semi-final, but Northampton showed that finishing the regular season in first place was no fluke.
Furbank raced over for the second time with six minutes left to ensure Northampton got the victory their thrilling attacking play deserved.
Fly-half Fin Smith was Northampton's man of the match with an influential display including five successful conversions.
"A lot of relief with how this season has gone. If we hadn't have got there, I think we would have felt like we had let ourselves down," he said.
Bath play Exeter in the second semi-final on Saturday, with Northampton lying in wait in the final at Twickenham on June 20.
