Francisco Leonelli grabbed a 15-minute hat-trick as rampant Saracens claimed their biggest league win of the season against an injury-hit Leeds to reignite their play-off hopes.

Leeds had 12 players out through injury and Saracens took full advantage with Nick Lloyd, Adam Powell, Hugh Vyvyan, Tom Ryder, Kameli Ratuvou, Glen Jackson and Brent Russell going over.

The result is the perfect preparation for Saracen's Heineken Cup quarter-final against the Ospreys at Vicarage Road and lifts Alan Gaffney's side up to sixth in the table.

Leeds meanwhile are 14 points adrift of safety and are staring relegation from the Guinness Premiership straight in the face.

Saracens broke the deadlock after six minutes when, from a powerful rolling maul, loose-head prop Lloyd crashed over the line.

Leeds full-back Leigh Hinton then pulled a penalty onto the posts before the home side moved up a gear.

Argentina international Leonelli grabbed the first of his treble after fly-half Jackson waltzed through the Leeds defence unopposed.

The hosts' young inside centre, Powell then produced a delightful show and go en route to the whitewash as Leeds disintegrated.

Saracens then wrapped up only their second try-scoring bonus point of the season in the 28th minute.

After recalled hooker Matt Cairns broke two tackles in the middle of the park, giant flanker Kris Chesney's lofted pass found Brent Russell in space on the right and the former Springbok put in Leonelli for a simple score in the right corner.

Jackson failed to add the extras but did take his tally to eight points when he converted Leonelli's third try eight minutes before the break.

Sarries started the second half in the same manner as they ended the first, lock Vyvyan crashed over on the left after gathering Ratuvou's grubber kick.

The blood-letting continued as replacement second row Ryder barged over as Leeds failed to contain a Sarries side building in confidence ahead of next weekend's clash against Ospreys.

Fijian wing Ratuvou then darted away from halfway for Saracens' eighth try which was converted by Jackson, and the Kiwi soon got in on the try scoring act when he took replacement Andy Farrell's pass into his stride.

Leeds, who offered so little all afternoon, avoided leaving Watford scoreless when former Sarrie Stuart Hooper benefited from a sloppy Jackson pass to score his side's solitary try.

James Brooks converted but Sarries had the last word when Russell notched his side's tenth try of a memorable afternoon.