Saracens came from 16 points to be at Harlequins and maintain a seven-point guide near the very surface of the dining table.
Hannah Casey and Sydney Gregson scored for Sarries at the final five minutes to make a 31-28 win in Allianz Park.
Harlequins had a healthy guide through Emily Scott, Heather Cowell and Jade Konkel, even though tries from Saracens’ Bryony Cleall and Hannah Botterman.
Loughborough Lightning narrowed the gap supporting second-placed Harlequins into three factors after beating Darlington Mowden Park Sharks 53-14.
Emily Tuttosi sprinkled down twice for Lightning and England captain Sarah Hunter also crossed, leaving the negative third in the table – 10 points clear from Wasps.
However, Wasps kept the pressure up, together with replacement wing Garnet Mackinder scoring two tries at a 38-12 defeat of Richmond.
Richmond had a direct lead through USA fullback Jess Wooden, however, four second half tries helped the people to success.
Recently named in the England squad, Gloucester-Hartpury wing Kelly Smith crossed four times to help her side defeat Worcester Valkyries 27-7.
Fellow England international Natasha Hunt was on the score sheet as Gloucester-Hartpury secured their eighth win of the season.
Bristol overcame rough terms to maintain back to back Premier 15s victories, defeating Firwood Waterloo 14-0.
Fly-half Lucy Attwood was horribly true from the tee strong winds and has been one of Bristol’s two try-scorers, along with fullback Cat McNaney.