Dan Biggar kicked a penalty in the 85th minute to seal a bonus-point Heineken Champions Cup victory for Northampton against Benetton after a second-half fightback.

Saints scored 17 second-half points with tries by Ollie Sleightholme and a second for Tom Collins before Biggar's decisive penalty.

Benetton led 25-15 at the break after tries by Hame Faiva, Iliesa Ratuva and Nacho Brex, but Collins and a Cobus Reinach try kept Saints in it.

The visitors move top of Pool One.

Saints made wholesale changes to their side from their opening-round victory over Lyon, replacing over half the team, but fly-half Biggar was one of seven players to retain his place.

The Wales international got his side off the mark with a comfortable penalty but the hosts seized the initiative when hooker Faiva powered over from close range.

Biggar then played a crucial role in the build-up to Collins' opening try for Saints with a no-look flick behind him to full-back Ahsee Tuala, who fed the winger.

Benetton regained the lead through Ratuva, but with the game evenly poised, Biggar took centre stage again after a dangerous tackle saw him spend the next 10 minutes in the sin-bin - something the hosts went on to exploit.

Centre Brex broke through in midfield before throwing a dummy to score his side's third try before Tommaso Allan kicked the Italians side further ahead.

But World Cup winner Reinach was alert to snipe through on the stroke of half-time, and with Braam Steyn in the bin for an accumulation of penalties, the visitors had a glimmer.

Sleightholme and Collins scored the tries to give Saints the lead, but a try from Faiva drew the scores level, before Biggar's late penalty completed his mixed afternoon to earn his side victory with the last play.

Saints are four points ahead of second-place Leinster, who travel to bottom side Lyon this afternoon, while Benetton remain third after picking up a losing bonus point.

Teams

Benetton: Hayward; Tavuyara, Brex, Benvenuti, Ioane; Allan, Duvenage; Zani, Faiva, Riccioni, Herbst, Ruzza, Pettinelli, Steyn, Halafihi

Replacements: Mancini Parri, Traore, Pasquali, Cannone, Snyman, Lazzaroni, Tebaldi, Keatley

Northampton: Tuala; Sleightholme, Proctor, Hutchinson, Collins; Biggar, Reinach; Van Wyk, Haywood, Franks, Moon, Ratuniyarawa, Gibson, Ludlam, Harrison

Replacements: Van Vuuren, Waller, Hill, Bean, Eadie, Mitchell, Dingwall, Furbank