Flood, who has dropped to third in the England fly-half pecking order, proved he was back to his best with a 25-point haul as Leicester demolished their great rivals 35-21 at Franklin’s Gardens, chalking up a fifth successive bonus-point win - a Premiership record.
Flood scored two of the Tigers’ four tries in the win - he also kicked three conversions and three penalties - with the others coming from wingers Alesana Tuilagi and Horacio Agulla.
Northampton’s tries came from England pair Lee Dickson and Chris Ashton, with Ryan Lamb kicking three penalties and Stephen Myler a conversion. England captain Chris Robshaw was among the try-scorers as Harlequins rubber-stamped their semi-final berth while plunging Wasps deeper into the relegation dogfight with a 33-17 success.
Robshaw was joined on the scoresheet by Ugo Monye, George Robson and Jordan Turner-Hall as Quins - for whom Rory Clegg kicked 13 points - secured a bonus-point victory.
But while it was all smiles for Quins the defeat rounded off a terrible day for Wasps, who saw relegation rivals Newcastle move to within four points of them after victory at Gloucester.
Dai Young’s side played some entertaining rugby at The Stoop with Christian Wade and Ross Filipo crossing for scores - and Nicky Robinson kicking seven points - but it was Quins’ day.
Delon Armitage marked his return to the London Irish starting line-up with two tries but they were not enough to save the Exiles from their seventh successive defeat - a 28-19 home loss to Saracens.
Armitage, who had been on the bench for the previous two matches, struck in each half for Irish, whose other nine points came from three Tom Homer penalties.
Saracens won the match on the back of an immaculate kicking display from England fly-half Charlie Hodgson.
He landed five penalties from five attempts, struck two drop goals and converted Sarries’ only try, scored by flanker Will Fraser.
But the victory was not enough to stop the reigning Premiership champions dropping from second to third as Leicester moved above them. Newcastle has recorded a stunning 29-20 victory at Gloucester to give them renewed hope of avoiding relegation.
The Falcons’ first league away win for almost 14 months was secured through tries by flanker Ally Hogg and replacement back-row forward Mark Wilson, while captain Jimmy Gopperth kicked 19 points.
Gloucester wiped out a 19-6 interval deficit to lead by a point with nine minutes left, but Newcastle finished strongly and are now just four points behind 11th-placed Wasps with two games remaining.
The home side conjured a try for flanker Akapusi Qera, with fly-half Freddie Burns booting five penalties, but Gloucester’s hopes of a Heineken Cup qualification were severely dented as they even failed to secure a losing bonus point.
Exeter produced an astonishing finish to record a remarkable 31-26 win over Worcester in a thrilling game at Sixways.
With less than two minutes of the game remaining they trailed 26-19 before tries from Phil Dollman and Sireli Naqelevuki and a conversion from Gareth Steenson broke the Warriors’ hearts.
Exeter also overcame the loss of two players to the sin-bin in the second half with wing Gonzalo Camacho fortunate to escape with a yellow card for a dangerous tip tackle.
