The odds on Bordeaux Bègles successfully defending their Champions Cup crown shortened considerably on a damp, grey Sunday lunchtime in Bristol. Good sides can adapt their game to suit awkward conditions and, for the second weekend in a row, French class outflanked English energy and optimism with a hat-trick of tries from the spectacularly prolific French winger Louis Bielle-Biarrey.

The Bears, seeking to play billionaire rugby on a day crying out for more prudent housekeeping, made far too many unforced errors and duly paid the price against opponents who are now perfectly placed in this year’s tournament. They will have the luxury of playing all their subsequent knockout games either on French soil or, if they reach the final, just across the Spanish border in Bilbao, and at this rate it will require something special to prevent them claiming back-to-back titles.

Even when their side are not quite at their best the sparkling Bielle‑Biarrey, along with the artful Matthieu Jalibert, give Bordeaux crucial extra stardust. On this occasion, with Bristol trailing by only five points entering the closing moments, it was Bielle-Biarrey who applied the crucial bonus-point dagger, outsprinting everyone to slither over for the game’s clinching score.

He had already claimed two first‑half tries inside nine minutes and was ultimately the difference on a day which, gloriously in this year’s pool stages, featured two teams at full strength, both desperate to win and aware of the consequences of not doing so. The knockout-stage high road could not have contrasted more starkly with the potholed pathway that Bristol will now be required to navigate.

Talking of contrasts, the difference in conditions from week to week in this tournament now verge on the ridiculous. Last week the Bears were at altitude in Johannesburg, desperately sucking in air and trying to keep cool. Now here they were back in Bristol in the rain and murk with a greasy ball and much more motivated opponents. They might as well have been on another planet.

What really mattered, though, was how swiftly they readjusted. Thirteen months ago Bristol were thumped 35-12 at home by Leinster in cold, damp and blustery conditions that did not suit them in the slightest. This was their opportunity to show how much they have subsequently come on and prove to themselves that they have the all-round game to live with the best.

The wet ball inevitably led to frequent mistakes but the game was never less than eminently watchable. Bristol scored first, turnover ball securing the field position from which the in-form Gabriel Oghre darted over, but avoidable errors increasingly played into Bordeaux’s hands.

First Louis Rees-Zammit unwisely kicked too long to an unmarked Jalibert and the ever-alert fly-half launched a compelling counterattack before liaising with his mate Bielle-Biarrey to his left. They made it look so simple it was almost possible to believe it might be an unfortunate one-off.

Which, of course, it wasn’t. Tom Jordan’s attempted pass to Benhard Janse van Rensburg went astray and when the loose ball eventually fell to Martin Page-Relo with Bielle-Biarrey outside him there was going to be only one result. When another Bears handling error deep in the Bordeaux 22 led to a kick-and-chase score finished by the centre Nicolas Depoortère, it was 17‑5 to the visitors inside half an hour.

Bristol just needed to settle down slightly and look after the ball. Instead George Kloska threw a pass out of the back door to no one in particular and Jordan was increasingly conspicuous by his absence. Bordeaux were winning the kicking battle and the home side’s usual slick rhythm was glimpsed only rarely.

The Bears were suitably grateful, then, for a 64th‑minute try from Janse van Rensburg, awarded despite some scepticism in Bordeaux ranks that the centre had properly grounded the ball. A Jalibert penalty, however, restored some order and despite a briefly encouraging Sam Worsley penalty it was Bielle-Biarrey who delivered the coup de grace.

It is still possible, of course, that a team such as Toulouse or Bath will gatecrash the party in the coming months but winning in south-west France tends to be easier to talk about than to achieve, as Northampton found this month.

On this occasion, too, Damian Penaud barely touched the ball. If he, Bielle‑Biarrey and Jalibert can all emerge from the Six Nations fit and well there will be even less reason to bet against another vintage Bordeaux season. “Every team knows that if you make mistakes against Bordeaux they will punish you,” Bristol’s director of rugby Pat Lam, said. “I can’t fault our effort but we gave them so many opportunities with our mistakes.”