Last week, all seven English teams lost, some of them badly, but on Sunday Wasps throttled La Rochelle 21-3 in Coventry, to gain some payback for a 20-point thrashing in France the previous weekend.
Saracens, beaten by 32 points at home by Clermont on Monday, did better in the return match, jumping to an early lead but conceding two penalties the last seven minutes to lose 24-21 in France.
Having come close against the Ospreys at home last week the third English team in action on Sunday, Northampton, this time lost more convincingly, 32-15 in Swansea.
In the final match of the weekend, Munster won 25-16 at Leicester to pull clear of second-place Racing 92 in Pool 4, after the French side had scored four tries in beating Castres 29-7 in their final match at the historic Stade Yves du Manoir. Leicester failed to collect even a bonus point and remain anchored to last place.
La Rochelle kicked off on Sunday on maximum points after collecting a bonus in winning each of their first three games.
Last week the French side produced an orgy of attacking rugby but on Sunday they were pinned back by a Wasps team seeking both revenge and a victory that would keep alive their hopes of advancing.
England winger Eliot Daly smashed over in the corner to give Wasps the lead after 11 minutes. He converted the try and did the same after touching down again in the 47th minute.
Wasps never allowed the visitors to develop their attacking game and La Rochelle scored their first and only points when Brock James kicked a penalty on the hour.
Wasps had the last word when replacement hooker Tom Cruse bulled over after a lineout. Danny Cipriani converted but Wasps could not add a fourth try to collect a bonus point.
Despite leaving the Ricoh Arena without even a losing bonus point, the French team remain first in Pool 1, two points ahead of Ulster, who crushed Harlequins on Friday, and five clear of third-place Wasps.