Saracens shrugged off their post-Northampton lethargy to reclaim top place in Pool Two of the Champions Cup by registering a bonus-point 36-34 victory over a spirited Ospreys at Allianz Park.

Six days after running in eight tries to send Saints tumbling to a record defeat at Franklin's Gardens, the European champions toiled against a team that props up Conference A of the PRO14.

The Ospreys overcame the loss of Wales back rows Justin Tipuric and Dan Lydiate to back injuries on the day of the match to accumulate a 17-7 lead by the 26th minute, crossing twice through full-back Dan Evans.

But Saracens used the boot of Owen Farrell and sin-binning of Evans to seize control, adding tries through Liam Williams and Nick Tompkins to pull clear after Chris Wyles and Schalk Brits had already touched down.

A penalty try awarded against Evans for a deliberate knock-on completed the Champions Cup holders' scoring, helping them extend their unbeaten European record to 20 games, while the Ospreys were at least able to claim a bonus point.

Crisp passing almost yielded an early try for Williams but Saracens could not be kept out at the ensuing scrum as smart handling from Farrell and Alex Goode sent Wyles over. It was the set-piece that provided the Ospreys with the platform to hit back almost immediately, Cory Allen drifting off the left wing to pop a pass to Evans when tackled and the full-back raced over.

The Welsh region were quickly back on the offensive and having patiently worked their way into the opposition 22, they struck through Evans who took Dan Biggar's pass and slipped between a large gap that had formed between Farrell and Mako Vunipola.

Duncan Taylor limped off to be replaced by Tompkins and as half time sounded, Saracens had drawn level. Brits started and finished the move that led to the fourth try of the half, sending a long pass to Williams who chipped ahead, before popping up on the left wing to capitalise on good footwork from Vunipola.

Evans almost completed his hat-trick shortly after the interval but dropped Biggar's pass with the line at his mercy and his hitherto perfect evening continued to unravel when he conceded a penalty try and was sent to the sin-bin.

Farrell's break made the Ospreys scramble and when Saracens later looked to exploit an overlap, Evans was guilty of a deliberate knock-on, although referee Marius Mitreas' decision to award a try under the posts looked harsh given cover was on its way.

A brilliant off-load from Tompkins while falling found Williams and the Lions wing raced over to grab the bonus point, but the Ospreys replied with a well-worked try from centre Owen Watkin.

Saracens' lead was now only two points, but Tompkins stretched his arm across the whitewash after Jamie George had galloped through a hole before Sam Cross crossed to clinch the bonus point for the visitors.