London Irish kept Pool 1 on the boil with their win at Mont de Marsan - and gave themselves another morale boosting lift.
They tackle Bordeaux-Begles at the Madejski Stadium in Round 6 with the win in France backing up their domestic success at Gloucester Rugby.
Brian Smith's team won their opening group game against Bordeaux-Begles 43-16 and will be looking for another French scalp to round off the Pool stages.
And in the process of banking the four points from that 20-14 win at Stade Guy Boniface they gave valuable game time and experience to players who will be key to their hopes in the second half of the season.
"We wanted to keep moving forward and keep getting better," said forwards coach Glenn Delaney.
"It was a very short turnaround after the Gloucester game and some guys have doubled up, playing both games."
Jack Moates scored a brace of tries, with his first coming in the 26th minute when he spotted a gap around the fringes after strong work from his pack. The 20-year-old's second was a result of Matt Garvey's charge down six minutes after the interval.
