Northampton advanced to the Champions Cup quarter-finals after a 49-41 win over Castres.
French side Castres went 12-0 up after just 10 minutes through tries from Christian Ambadiang and Theo Chabouni, before Saints were awarded a penalty after Ambadiang was shown a yellow card for a lively tackle.
Castres were reduced to 13 men when lock Guillaume Ducat received another yellow for catching Henry Pollock in a ruck, but extended their lead with a penalty kick before Danilo Fischetti went over at half-time with Saints trailing 15-14.
Henry Pollock protects the ball as Castres players rush in.
The hosts took the lead for the first time five minutes into the second half when Archie McParland’s pass was picked off by Josh Kemeny and the lead increased to 13 points when Tommy Freeman got on the scoresheet.
The deficit went back to one after tries from Tyler Ardron and Vuate Karawalevu, but goals from George Furbank and McParland put the Saints back in charge.
The lively Ambadien scored but was conceded late in the game.
Vilimoni Botitu reduced the arrears to eight but Castres lost Veresa Ramotabua to a sin-bin and Northampton took the advantage when Fraser Dingwall went down.
Ambadiang had the last word with a last-minute strike in the middle, but Saints came home on the hose, booking a tie with either Bath or Saracens in the last eight games.
