James Lang's nerveless conversion deep into injury time completed a sensational comeback for Harlequins as they kicked off their Anglo-Welsh Cup campaign with a 30-29 win at Saracens.

Tries from Harry Sloan, Alofa Alofa and Elia Elia looked to have been in vain as Quins battled back from a 26-5 deficit but Josh Ibuanokpe dotted down late on and Lang split the posts to finish with a 10-point haul.

Jack Nay, Nathan Earle and Tom Whiteley crossed for the Aviva Premiership leaders, who saw the boot of 20-year-old fly-half Max Malins score 14 points.

With both sides missing several regulars on international duty, only Nick Tompkins remained from Saracens' win over London Irish, while Harlequins made 12 changes of their own.

Having gone behind to an early Malins penalty, Quins struck back through Sloan, who was slipped through by Lang after Ben Glynn stole possession inside Saracens' 22.

Try number two nearly arrived a couple of minutes later, but stand-in captain Charlie Mulchrone knocked-on while off-loading for what would have been a certain score when three yards out.

The away side were constantly let down by their discipline at the breakdown in the first half, and two further Malins penalties put Saracens back on top.

Alofa Alofa of Harlequins scores a try (Getty)

Nay extended the lead in the 36th minute when he broke clean through in midfield, shrugged off the attentions of Tim Visser and Gabriel Ibitoye and tumbled over the line, with Malins adding the extras.

Christopher Tolofua and Will Skelton then combined early in the second half to send Earle over in the corner for his fourth score of the season.

Saracens' third try came when captain Ben Earl seized on a loose ball, charged 30 yards through an open defence and fed Whiteley, who completed the easiest of finishes.

Samoan international Alofa pulled a try back for Quins when he bundled his way through three tackles to stretch over from close range, which Lang converted.

Relentless Harlequins pressure was rewarded when Alofa's countryman Elia dotted down in the corner to cut the gap to nine, but Lang could not convert.

A minute later, Whiteley's phenomenal try-saving tackle on full-back Visser prevented the Scot from scoring as he was about to touch down out wide.

Lang then traded penalties with Malins before the Quins kicker converted another from the tee to put his side within a converted try of victory.