Troubled Wasps were unable to improve their chances of avoiding relegation from the Aviva Premiership, losing 32-15 defeat at Northampton.
A 10th defeat in 11 games leaves them just eight points above bottom club Newcastle, who lost to Worcester on Friday night, and their showdown at Wasps' ground in the final game of the season could decide who drops into the Championship.
Northampton's sixth win in their last eight games moved them into third place above Leicester, who meet London Irish on Sunday, and while they deserved to win they left it until the 75th minute to score the bonus point try.
That came from substitute scrum-half Martin Roberts, the others going to England full-back Ben Foden (2) and centre James Downey, with Ryan Lamb kicking two penalties and two conversions and replacement fly-half Stephen Myler a penalty.
Wasps' points all came from the boot of fly-half Nicky Robinson, who kicked five penalties.