Louw's dramatic intervention from the base of a ruck just a metre shy of the Agen line provided a fitting finale to a compelling encounter in which the lead changed hands five times at the Stade Armandie.

Agen looked set for a second successive win themselves after Raphael Lagarde kicked his fifth penalty with nine minutes remaining but Louw's late, late converted score made it 27-22 as Bath stunned the home support at the death.

The South African's effort also brought Bath a try-scoring bonus point, with the visitors having earlier crossed through scrum-half Michael Claassens, wing Kyle Eastmond and fly-half Stephen Donald.

Agen actually led for the entirety of the first half as Benjamin Petre touched down with just three minutes played and Lagarde added a 21st-minute penalty to his successful conversion.

But Bath scored three times in a 20-minute spell either side of the break, with Claassens cutting the gap on 33 minutes, Eastmond leveling the scores after 46 minutes and Donald giving Bath a 20-16 lead after Lagarde had kept the scoreboard ticking over for the hosts.

The other fixture in this pool sees Bucharest Wolves host Cammi Rugby Calvisano in Romania after both those sides lost their opening fixtures.