European Champions Cup: Leinster 57-3 Montpellier

Leinster will guarantee a home quarter-final if they beat Castres in their final pool fixture

Impressive Leinster powered to a huge win over Montpellier to become the first team to qualify for the last eight of the European Champions Cup.

Second-row Jack Conan scored a hat-trick of tries for the dominant hosts.

Full-back Ica Nacewa, winger Adam Byrne, scrum-half Luke McGrath, replacement prop Cian Healy and centre Garry Ringrose also touched down.

Montpellier had fly-half Frans Steyn red-carded for a high challenge on Johnny Sexton when the score was 14-3.

Leinster, bottom of their group last season, can clinch a home quarter-final by beating Castres on 20 January.

Montpellier fly-half Frans Steyn was sent off for a high tackle on his opposite number Johnny Sexton

Red card for reckless tackle

There seemed to be little doubt over referee JP Doyle's decision to send off South African Steyn for taking out Sexton high and with force on 26 minutes.

The official reviewed the challenge and consulted assistant Wayne Barnes before producing the red card.

Montpellier's third sending-off in as many European games and, under the new regulations, the French club had little room for complaint.

Relentless Leinster took full advantage by securing a crushing victory over the 14 men to move nine points clear at the top of Pool Four.

Former Ireland captain Brian O'Driscoll was impressed by Leinster's dazzling display

Nacewa and Conan had already scored tries by the time of Steyn's dismissal and winger Byrne snapped up another before the break.

Conan got his second try soon after the restart, Sexton's conversion taking the Ireland fly-half past the 500-point mark in Europe.

Montpellier, who won October's home fixture 22-16, seemed to switch off and Luke McGrath spotted a gap to burst through for try number five.

Further tries followed from Healy and Ringrose, with Conan's hat-trick score in between.

Leinster: Nacewa, A. Byrne, G. Ringrose, Henshaw, O'Loughlin, Sexton, L. McGrath, J. McGrath, Tracy, Furlong, Toner, Triggs, Conan, van der Flier, Heaslip.

Replacements: R. Kearney for Nacewa (42), R. Byrne for Sexton (28), Gibson-Park for L. McGrath (65), Healy for J. McGrath (53), Strauss for Tracy (56), Bent for Furlong (56), Molony for Triggs (64).

Not used: Leavy.

Montpellier: Michel, Nagusa, Martin, Tomane, Nadolo, Steyn, White, Nariashvili, Mamukashvili, J. du Plessis, Willemse, Mikautadze, Ouedraogo, Qera, Spies.

Replacements: Mogg for Martin (72), O'Leary for White (60), Watremez for Nariashvili (53), Geli for Mamukashvili (41), Kubriashvili for J. du Plessis (53), Battut for Mikautadze (41), Galletier for Ouedraogo (64).

Not used: Immelman.

Sent off: Steyn (27).

Referee: JP Doyle (England)