Johan Ackermann promised his Gloucester side would “give it their best shot” as they face a daunting must-win trip to Toulouse next weekend to have any chance of reaching the European Champions Cup quarter-finals.

A 29-6 bonus-point win over a weakened but spirited Montpellier at Kingsholm kept hopes alive but Toulouse are unbeaten, ensuring they will top Pool 5, and they beat Gloucester 25-20 at Kingsholm.

Gloucester’s tries came from Willi Heinz, Louis Rees-Zammit, Ben Morgan and Todd Gleave. Billy Twelvetrees converted three and added a penalty, while François Steyn and Thomas Darmon kicked penalties for Montpellier.

Ackermann said: “It’s bizarre that we’ve lost three games and the pool has been all about what-ifs but we are still in with a chance of qualifying. It’s a big game for this group but it’s a nice challenge to have, so we’ll give it our best shot and anything is possible.”

For the third home game in a row, Gloucester were poor in the first half but on each occasion, their second-half performance was vastly improved. After beating Worcester 36-3 and Bath 29-15 in the league, they were able to repeat the feat in Europe by scoring three tries in a one-sided second half.

Ackermann said: “The boys showed a lot of character and it’s great to see the growth of the side. However, the first half was not good enough as we needed to be patient and keep the ball against a massive team. We threw 50-50 passes and lost ball in contact but we knew that the longer the game went on, the more we would come into it, which is what happened in the game out there.

“The second half was a lot better as our physicality remained and the backs played with speed. It was a priority to win but to get a bonus point was indeed a big bonus.”

Heinz, the captain, added: “We were pretty poor in the first half through our own inaccuracies as we wanted to hold the ball and take them through the phases. Their aggressive defence put us off our stride but in the second half, we managed to get our game plan going and move the ball wide.

“Next week is an exciting opportunity. It’s these games you’ll remember when you’ve retired and we are really thrilled to be playing in a magnificent stadium.”

Clermont Auvergne secured their place in the quarter-finals of the Champions Cup with a 29-13 Pool 3 victory over Ulster at the Stade Marcel Michelin. Ulster host Bath on Saturday, where a win would put them in the last eight with Clermont.

Louis Rees-Zammit scores the second try for Gloucester in their bonus-point win at Kingsholm. Photograph: Simon Galloway/PA

Tries from Alivereti Raka, George Moala and 16 points from the boots of Morgan Parra and Greig Laidlaw were enough to secure victory for the French side. John Cooney scored all Ulster’s points with a try, conversion and a penalty.

“We are bitterly disappointed,” said the Ulster coach, Dan McFarland. “It was a game we had control of in the first half and we didn’t make our pressure pay when we should have done. If you are going to be good enough to win in Clermont and they are down to 14 men and you kick to the corner and you can’t score tries, then you aren’t a good enough team to win in Clermont.”

Connacht’s head coach, Andy Friend, bemoaned his side’s lack of accuracy in their 21-7 Pool 5 defeat to Toulouse at the Sportsground. The hosts, whose unlikely chances of progression required a bonus‑point win – led early through a penalty try. But converted scores from Jerome Kaino, Julien Marchand and the former Connacht back Pita Ahki booked Toulouse’s quarter‑final spot with a fifth straight pool victory.

Friend felt Connacht’s execution let them down on the day, especially when considering the replacement Yoann Huget’s yellow card and the fly-half Zack Holmes’ sending-off during the final nine minutes, which left the French side finishing the game with 13 men.

Friend said: “I thought our intent was really good and that we showed a lot of energy. It’s just our execution that let us down and it’s not where it needs to be in a Champions Cup game. That’s where we lost it. But I suppose it’s a plus to have our intent back and our desire back.

“We’ve just got to make sure we’re more clinical next time. I thought our defence was somewhere, we fronted up, getting double shots and bouncing, and it was much, much better [than in the recent Pro 14 defeats].”