Miller show moves Wasps closer to semifinals
Miller's man-of-the-match performance kept the pressure on Exeter Chiefs but Wasps narrowly missed out on the all important fourth try and subsequent bonus point.
The fullback's brace was added to by Jamie Cooper's effort in the dying minutes and kicks from the boots of Jimmy Gopperth and Elliot Daly sealed the victory as Saints could only muster two Stephen Myler penalties.
Saints took a second-minute lead as Myler slotted a penalty from just inside Wasps territory.
Six minutes in and Wasps thought they had scored with their first possession in the game but the TMO ruled Miller was held up just shy of the line, by Teimana Harrison, having danced through the Saints defence.
Wasps should have been level on the quarter hour mark but Gopperth struck his kick against the upright – he made no mistake two minutes later though.
Saints then suffered a blow as prop Kieran Brookes was replaced by Paul Hill after his head collided with Ashley Johnson in the tackle.
And Wasps' ascendancy continued after 20 minutes as George Smith broke clear in his own half and fed the supporting Thomas Young who in turn off-loaded to Miller who made no mistake this time, with Gopperth adding the extras.
Both sides traded turnovers and attacks for the remainder of the first half but neither could make a definitive line break.
Jon Fisher came on to replace Saints No,8 Sam Dickinson at half time and the second period's opening minutes saw the visitors steal two line-outs from Johnson, but they could not convert them into points.
Elliot Daly and Myler then traded penalties either side of 50 minutes as each side was penalised at the scrum and moments later Harry Mallinder escaped the sin-bin for a high tackle on Christian Wade.
Daly then came up short with another long-distance effort and after the hour mark was involved in a scramble with Saints replacement Lee Dickson that led to the scrumhalf being helped from the pitch and straight down the tunnel.
Courtney Lawes and Ben Foden combined well for a Saints break down the right touchline with 15 minutes to go but Northampton could not maintain territory and Wasps soon put the game beyond their reach.
It was Miller who grabbed his second of the day, bursting through the visitor's defence to run in from 40 metres and, with Gopperth's conversion, increase his side's lead to 14 points.
A blistering break from inside their own 22 by Saints' Tom Collins brought the visiting fans to their feet but when he was stopped just inside Wasps territory another Daly penalty further extended the Wasps lead.
The scoring was then complete when replacement Stevenson collected the ball from a five-metre scrum for a simple finish in the right corner, but Gopperth could not add the finishing touch.
The loss for Saints not only dents their hopes of a semifinal spot, it guarantees Saracens' involvement in the post-season showdowns.
The scorers:
For Wasps:
Tries: Miller 2, Stevenson
Cons: Gopperth 2
Pens: Gopperth, Daly 2
For Northampton:
Pens: Myler 2
Wasps: 15 Rob Miller, 14 Christian Wade, 13 Elliot Daly, 12 Siale Piutau, 11 Frank Halai, 10 Jimmy Gopperth, 9 Craig Hampson, 8 Nathan Hughes, 7 George Smith, 6 Thomas Young, 5 Bradley Davies, 4 Joe Launchbury, 3 Jake Cooper-Woolley, 2 Ashley Johnson, 1 Matt Mullan (captain).
Replacements: 16 Carlo Festuccia, 17 Simon McIntyre, 18 Lorenzo Cittadini, 19 Kearnan Myall, 20 James Haskell, 21 Jamie Stevenson, 22 Ruaridh Jackson, 23 Sailosi Tagicakibau.
Northampton: 15 Ben Foden, 14 Ken Pisi, 13 George Pisi, 12 Harry Mallinder, 11 George North, 10 Stephen Myler, 9 Kahn Fotuali’i, 8 Sam Dickinson, 7 Teimana Harrison, 6 Tom Wood (captain), 5 Christian Day, 4 Courtney Lawes, 3 Kieran Brookes, 2 Mikey Haywood, 1 Alex Waller.
Replacements: 16 Reece Marshall, 17 Campese Ma’afu, 18 Paul Hill, 19 James Craig, 20 Jon Fisher, 21 Lee Dickson, 22 JJ Hanrahan, 23 Tom Collins.
Referee: Luke Pearce
Assistant Referees: Andrew Jackson, Robin Goodliffe
TMO: Geoff Warren