Harlequins’ miserable league run continued with their fourth straight Premiership defeat after a red card for captain Stephan Lewies ruined any chance of them ending that sequence against London Irish.

Lewies was sent off for a dangerous challenge to the head of opposition No 8 Chandler Cunningham-South, and Irish took full advantage with a bonus-point victory to leave them just one point behind Quins in the Premiership table.

Michael Dykes scored a hat-trick of tries, Cunningham-South, Tom Pearson and James Stokes the others with Paddy Jackson converting all six in a 42-24 victory.

Quins’ response was a penalty try award and tries from Tommy Allan, Dino Lamb and Josh Bassett. Allan also added a conversion.

Irish began strongly to take a fourth-minute lead. Twice they declined kicks at goal in favour of attacking line-outs and were rewarded when Cunningham-South crashed over from the second.

Three minutes later the hosts scored again when Stokes made the initial burst before feeding Pearson, whose pass provided Dykes with an easy run-in.

Jackson converted both for his side to have a 14-0 lead at the end of one-sided first 15 minutes but Quins finally got a foothold in the match.

A strong run from Nick David secured the visitors a platform in the Irish 22 before they were awarded a penalty try when Dykes deliberately knocked on to prevent a score from David.

The Irish wing was yellow-carded but immediately they received a boost when Stokes capitalised on a favourable bounce to run 30 metres to score.

After Jackson had converted, TMO replays showed a dangerous challenge from Lewies and the Quins’ flanker was sent off.

The home side then suffered two blows in quick succession. Australia international lock Adam Coleman departed with a serious arm injury before David tore their defence to shreds to create a try for Allan.

Dykes returned from the sin-bin before Irish received a further setback when prop Will Goodrick-Clarke departed with a leg injury.

However, they overcame this to score their bonus-point try from Dykes with another successful kick from Jackson giving Irish a 28-12 interval lead.

Four minutes after the restart, Dykes supported a break from Ben White to complete his hat-trick before Irish introduced Henry Arundell for his first appearance since September.

Spirited Quins remained in the fight when first a clean break from Andre Esterhuizen created a try for Bassett before Lamb forced his way over to earn a bonus point.

Irish’s nerves were jangling but Joe Marler was yellow-carded for collapsing to put an end to any hopes of a remarkable Quins’ comeback with a late try from Pearson sealing victory.