Saracens host Italians Viadana at Vicarage Road attempting to take the initiative in a competitive pool 4.

Alan Gaffney’s side have made a bright start to the campaign with a bonus-point 33-31 win over Glasgow and a narrow 22-21 bonus-point defeat to Biarritz and are boosted by the arrival of All Black lock Chris Jack who is likely to make his debut.

Saracens, who made the EDF Energy Cup semi-finals last weekend, have won their last five home matches in Europe’s premier tournament and did the double against fellow Italian opposition Treviso two years ago.

Viadana have never won away in the Heineken Cup before and it would be a major shock to the competition if Jim Love’s men could do so in London on Saturday afternoon.