European Challenge Cup: Sides learn knockout opponents in second-tier tournament

21 January

Gloucester will aim to continue their unbeaten run in the Challenge Cup when they host Castres in the last 16.

Top seeds Sharks are the other unbeaten side in the tournament and the South Africans host Zebre.

The qualifiers come from the top four sides in the three pools with Connacht, Ulster, Bayonne and Sale dropping down from the Investec Champions Cup.

Ospreys host Sale Sharks, Ulster travel to face Montpellier, while Pau will entertain Connacht.

All fixtures are to be played on the weekend 5-7 April.

Edinburgh have a home tie against Bayonne, while Lions will travel to face Benetton and Clermont Auvergne entertain Cheetahs.

Ospreys are the only Welsh side to have reached the knockout stages of either European competition.

Dragons, Oyonnax, Newcastle, Perpignan, Black Lion and Scarlets are out after finishing in the bottom two of their pools.

Last-16 fixtures

Sharks v Zebre

Gloucester v Castres

Benetton v Lions

Clermont Auvergne v Cheetahs

Montpellier v Ulster

Pau v Connacht

Ospreys v Sale Sharks

Edinburgh v Bayonne

Last 16 - 5/6/7 April

Quarter-finals - 12/13/14 April

Semi-finals - 3/4/5 May

Final - 25 May.