The last two occasions Northampton Saints have qualified for the European Rugby Challenge Cup quarter-finals, they have gone on to win the trophy. However, they face a difficult task on March 31, when they visit fellow two-time winners ASM Clermont Auvergne, live on BT Sport, FR4 and beIN SPORTS. Here are five possible key figures. Dan Biggar The goal-kicking Wales fly-half is in his 11th season of European rugby, after 10 seasons with Ospreys, and has scored 20 points in his four Challenge Cup appearances for Northampton this term. The 29-year-old is the go-to man if things get tight with his pinpoint kicking from hand and tee. Luther Burrell Burrell, 31, is already a Challenge Cup winner with Northampton, having played in their 2014 success, and will be eager to bow out with another medal before switching codes. The former England centre has been an ever-present in the competition this season, scoring two tries. Teimana Harrison The former England back-row forward is sure to be watched closely if he gets the nod to face Clermont, as he scored a hat-trick of tries in Northampton’s thrilling 48-40 loss there in Round 5. The New Zealand-born 26-year-old is a real threat with ball in hand and a tenacious tackler. Alex Mitchell The 21-year-old scrum-half has made a big impression in his first full European campaign this season, scoring six tries in six appearances, including a hat-trick against Timisoara Saracens in Round 6, to lie joint third in the try-scorers' chart. Tom Wood Wood skippered Northampton to their last Challenge Cup title in 2014 and the 32-year-old back-row forward is still an important member of the Saints set-up. Altogether the England international, who won 50 caps, has made 62 European appearances, including four this term.