Toulouse will return to France with a bonus-point win after their match with Zebre was abandoned after 63 minutes due to fog.
Two Carlo Canna penalties to Sébastien Bezy’’s one gave the Italian outfit an early 6-3 advantage, but the French side hit back with 33 unanswered points.
Arthur Bonneval (twice), Gael Fickou, Yoann Huget and Joe Tekori all went over as they moved 36-6 clear in the second half.
With conditions worsening, referee Ian Davies decided to end the game 15 minutes early due to thick fog, meaning that Toulouse went away with a comfortable win.
Having gone down to Connacht in Round 1 and only drawn at home to Wasps a week later, the visitors needed a victory to ignite their campaign.
However, their start was inauspicious, going down 3-0 to a Canna penalty. Although Bezy responded with one of his own, the hosts’ fly-half regained their three-point buffer.
Following that bright beginning, that was as good as it got for the Parma-based outfit whose fragile defence allowed the away team to open up a comfortable advantage by the interval.
Bonneval crossed the whitewash first before Fickou followed 12 minutes later for a 15-6 lead after half-an-hour.
That score was the catalyst for the floodgates to open and Tekori soon touched down, powering over after concerted pressure.
When Huget finished an excellent move on the stroke of half-time, the French outfit went into the break 29-6 ahead.
Seven minutes into the second period and Bonneval scored another try but, with the weather worsening, Davies called an end to the match as the visitors went away with the five points.
Pens: Canna 2
Tries: Bonneval 2, Fickou, Tekori, Huget
Cons: Bezy 4
Zebre: 15 Edoardo Padovani, 14 Mattia Bellini, 13 Tommaso Boni, 12 Tommy Castello, 11 Dion Berryman, 10 Carlo Canna, 9 Guglielmo Palazzani, 8 Federico Ruzza, 7 Johan Meyer, 6 Derick Minnie, 5 Gideon Koegelenberg, 4 Quintin Geldenhuys, 3 Dario Chistolini, 2 Tommaso D’Apice, 1 Bruno Postiglioni
Replacements: 16 Carlo Festuccia, 17 Guillermo Roan, 18 Pietro Ceccarelli, 19 Valerio Bernabo, 20 Josh Furno, 21 Carlo Engelbrecht, 22 Matteo Pratichetti, 23 Giambattista Venditti
Toulouse: 15 Alexis Palisson, 14 Yoann Huget, 13 Florian Fritz, 12 Gaël Fickou, 11 Arthur Bonneval, 10 Jean-Marc Doussain, 9 Sébastien Bezy, 8 Gillian Galan, 7 Francois Cros, 6 Joe Tekori, 5 Edwin Maka, 4 Richie Gray, 3 Dorian Aldegheri, 2 Julien Marchand, 1 Cyril Baille
Replacements: 16 Christopher Tolofua, 17 Gurthrö Steenkamp, 18 Census Johnston, 19 Thierry Dusautoir, 20 Gregory Lamboley, 21 Luke McAlister, 22 Toby Flood, 23 Paul Perez
Referee: Ian Davies (Wales)
Assistant Referees: Simon Rees (Wales), Jonathan Hardy (Wales)
TMO: Neil Hennessy (Wales)