Montpellier kept the group nicely on the boil with a 34-21 bonus point victory over struggling Cardiff Blues at Stade Yves du Manoir that drew them level with Toulon - who have a game in hand - on 13 points apiece.
The double over the Welsh club was their third win of the tournament but if Toulon get anything from their clash with Sale Sharks they will go back out on their own.
Wales captain Sam Warburton, who missed the Round 3 encounter with a chest infection, gave the Blues a flying start with a fourth minute try from an overthrown line-out before Martin Bustos Moyana and Rhys Patchell - who kicked all the Blues' points in their 35-24 defeat at the Arms Park in Round 3 - exchanged penalties.
And another player getting into the scoring action again was Montpellier's right wing Timoci Nagusa, one of their try scorers in Wales breaching the Blues defence on home soil this time as he scrambled over despite the close attentions of a number of Blues players.
Hooker Rassie van Vuuren got their second after 26 minutes and Bustos Moyana's conversion allowed them to go into the break with a nine-point advantage.
Yoan Audrin, another to score in the back-to-back contests, eased Montpellier further ahead before Wales wing Alex Cuthbert went over for his fourth Blues try of the campaign to give them a glimmer of hope.
But Scotland international back rower Johnnie Beattie wrapped up the try bonus point with 24 minutes still on the clock which prompted the home club to make a raft of replacements.
