Dan Biggar could miss Lions' warm-up clash with Japan if cited over clear-out in Saints victory over Wasps

• Northampton Saints 30 Wasps 25

Dan Biggar could miss the Lions' warm-up clash with Japan if he is cited over a dangerous clear-out in Saints' victory at Franklin's Gardens.

Referee Adam Leal failed to act at the end of the contest when the Wales fly-half was clearly seen to strike Jacob Umaga in the head with a forearm at a ruck.

If he is cited, Bigger could be hit with a three- or six-week ban. Wasps boss Lee Blackett was clearly upset with the fact Biggar's actions were missed and said: "I don't think he wanted to look at it. I thought the TMO chose when he wanted to come in and when he didn't want to come in throughout the game. The problem is, I think you've got young officials out there on the field, but that's where you need the experience to make the big decisions and calls."

A ban would be a blow for the player who was outstanding in kicking 13 points and engineered this win which assured Saints of Champions Cup exploits again next season, even if Harlequins' win over Bath meant they missed out on the playoffs.

Saints director of rugby Chris Boyd praised both Bigger and Courtney Lawes, who returned to action in his bid to regain match fitness in time for his second Lions tour.

Lawes, 32, showed no rustiness, as he returned from a five-month injury absence to his scrapping, carrying best, while Bigger kicked outstandingly from hand and turf to leave his rivals facing defeat.

Boyd enthused: “Courtney is a world-class player. He makes a big difference. We asked him how he was feeling after 70 minutes and he came back with a bundle of expletives to suggest he’d done his shift. He was aching and puffing a bit by then. But he was outstanding for us on his return.

“Dan Biggar trained well this week and he was also orchestrating things out there again. He will be all the better for that run-out and played a major role again.”

Lawes defied his lack of game time to produce the kind of performance which made him a Lion in New Zealand four years ago, and show why Warren Gatland has given him another chance to shine in the prestigious red jersey.

A watching Eddie Jones would have been pleased to see Lawes back on the field even if he is unable to pick him for any of England’s summer Tests.

Lawes was immediately involved in adding his muscle to the move which put Saints on the way to victory.

A simple lineout drive pushed Wasps back over their own line, and hooker Sam Matavesi rose to take the slaps on the back from his teammates. Biggar added the extras but Wasps responded with an outstanding piece of opportunism from Thomas Young. The flanker demonstrated a commendable turn of pace to burst through the middle of the Saints defence before offloading one-handed to the supporting Dan Robson to run over unchallenged.

Umaga converted but the fly-half was soon leaving the field after being shown a yellow card by the referee for deliberately kicking the ball away near his own line from an offside position with Wasps on the attack.

Wasps captain Brad Shields then bulldozed his way over for a try, Charlie Atkinson converting. Biggar and Umaga exchanged penalty blows and the two sides were all square at the break.

In the second half, Ollie Sleightholme rescued Saints by chasing down Josh Bassett as the Wasps wing made a break, while the visitors had a try by Zach Kibirige ruled out for a forward pass.

Biggar kicked his side back in front from a scrum penalty. Another Biggar penalty increased the lead. Flanker Tom Wood then forced his way over for a try to put the game beyond the visitors as Tom Willis' late scores failed to save Wasps from defeat.

Match details

Northampton: Freeman, Sleightholme, Proctor, Dingwall, Naiyaravoro, Biggar, James, Waller, Matavesi, Hill, Ribbans, Ratuniyarawa, Lawes, Ludlam, Wood.
Replacements: Haywood, Iyogun, Painter, Moon, Coles, Tupai, Francis, Hutchinson.

Wasps: Atkinson, Kibirige, Odogwu, Le Bourgeois, Bassett, Umaga, Robson, West, Oghre, Alo, Rowlands, Gaskell, Shields, Young, T. Willis.
Replacements: Cruse, McIntyre, Toomaga-Allen, Cardall, Vailanu, Vellacott, Gopperth, Miller.

Referee: Adam Leal (RFU)