Roberts grabs bonus for sloppy Saints

Northampton Saints 32 London Wasps 15

Clean pair of heels: Ben Foden breaks on his way to two tries for Northampton (Getty Images)

Not even their greatest supporter would say that last week was memorable in Northmapton's long history. Disciplinary issues, and defeat in the domestic cup final by their closest rivals, Leicester, cast shadows which will not have been entirely lifted by yesterday's hard-working win over London Wasps which nudged them up to third in the Aviva Premiership table.

The longer the second half went on, the more likely it became that Northampton might even squander a fourth try and a bonus point. When Martin Roberts finally scampered clear from a five-metre scrum with only five minutes remaining, the relief around the ground was almost palpable after a period in which Northampton dominated every statistic but the one that counted – the scoreboard. "We weren't 100 per cent accurate, a little rusty in a few places but Wasps never gave in," said Jim Mallinder, Northampton's director of rugby.

Chris Ashton returned to club colours for the first time since January but he, like Northampton, was misfiring. Even so, they found themselves clear at the interval, three tries to the good despite Ryan Lamb's inaccuracy in front of goal and the referee's decision that the apparentlydominant scrum – Northampton's – was at fault, helping Nicky Robinson to the three penalties which kept Wasps in the hunt.

Indeed, Wasps led 9-7 on the half-hour and could say that the Northampton try came against 14 men; Waldouck was receiving treatment on the pitch as George Pisi slid through the midfield a grubber kick seized by Ben Foden for the first try. Fifteen points in 11 minutes changed matters: James Downey streaked through behind a scrum for the sort of try which gives defence coaches the vapours and Ashton's persistence led eventually to a second try for Foden, with Lee Dickson making the extra man.

When the teams re-appeared for the second half, Northampton were without Tom Wood, the England flanker who missed the Six Nations because of a toe injury and now has a fresh one (on the same foot) which is creating problems. He was soon joined on the side lines by Andy Long and Ben Broster, the two front-row forwards going to the sin bin after a mêlée. Two further penalties by Robinson, who subsequently collected a yellow card himself, nudged Wasps closer to the possibility of a losing bonus point, a hope snuffed out by Roberts. "The frustrating thing for me is that we have to work so hard to get any points and then we leak silly points like the scrum [Downey's] try," David Young, the Wasps director of rugby, said. "I'd be lying if I said I wasn'trelieved that Newcastle lost, we still have a cushion but that can be eaten away very quickly."

Meanwhile, Exeter remained on course for the play-offs after claiming a dramatic 28-27 victory against Gloucester at Kingsholm. Substitute lock Aly Muldowney's last-gasp try, which was awarded on the judgement of the television match official, Tony Spreadbury, and converted by Muldowney's replacement, Gareth Steenson, gave the Chiefs a seventh win from their past eight away games.

Sale Sharks's first-team coach, Tony Hanks, has left the club following Friday's 45-9 home defeat by Saracens. Sale have lost 10 of their 18 Premiership games this season.

Wales' Grand Slam-winning captain Sam Warburton is set to return to action in six weeks after being told that he has "no structural damage" to his shoulder.

Northampton: B Foden; C Ashton, G Pisi (T May, 73), J Downey, P Diggin; R Lamb (S Myler, 68), L Dickson (capt; M Roberts, 71); S Tonga'uiha (A Waller, 64), A Long (R McMillan, 76), B Mujati (P Doran-Jones, 59), J Craig (T Harrison, 71), C Day, P Dowson, R Wilson, T Wood (M Sorenson, 41).

London Wasps: H Southwell (capt; T Prydie, 73); J Wallace, E Daly, D Waldouck (P Emerick, 18), R Haughton (C Davies, 79); N Robinson, N Berry; T Payne (Z Taulafo, 64), T Lindsay (V Korshunov, 56), B Broster, J Cannon, R Birkett, J Launchbury (S McIntyre, 56-61), S Jones, J Poff (J Hart, 42).

Referee: T Wigglesworth (Yorkshire)