Scrum-half Dave Lewis inspired Harlequins to a 35-7 win over Scarlets and helped his side put one foot into the semi-finals of the Anglo-Welsh Cup.
Lewis, who joined Quins from Exeter at the start of the season, scored once and had a hand in two other tries as his side made it three from three in the tournament.
Henry Cheeseman, Archie White, James Lang and Ross Chisholm also crossed as their side moved to within a point of the last four.
Quins head to Northampton in the final round next week whilst Chiefs, in second and five points back, entertain Saracens.
By the time Lewis was replaced, his side had the try bonus point wrapped up on the back of a powerful performance from their pack.
Veteran prop Mark Lambert, in his 224th game for the club, was the stand-out forward with a carrying and scrummaging display that belied his 32 years.
Flanker Luke Wallace made his first start of the season for the hosts, after a hip injury, and centre Joe Marchant was in the run-on XV after playing two minutes since the end of October.
The visitors had one early penalty which fly-half Jacob Botica pushed wide but the experience of Quins told as they headed to the break 14-0 up thanks to tries from centre Cheeseman and Lewis.
Cheeseman's score came in the 21st minute when Lewis darted from a five-yard scrum to put the midfielder over from short range.
And five minutes later Lewis got a score of his own, going over after a lineout drive from his pack put the Scarlets on the back foot.
The Scarlets had hardly touched the ball in the second half when Quins flanker White went over for his team's third try in the 46th minute after yet more pressure from the hosts.
At 21-0 down Scarlets started to put together some phases but Harlequins relieved the pressure with a break that ended with Cheeseman knocking-on Lewis' chip over the try-line.
But Quins got the try bonus point on 58 minutes when Lewis fed fly-half Lang who ghosted in under the posts before replacement Bryce Morgan's consolation.
Even that was wiped out by Chisholm's 40-metre score in the final couple of minutes for a dominant Quins.