The 33-year-old Welsh international – who played for the Parisian club between 2013 and 2015, when they were known as Racing Metro 92 – feels they will be looking for some sun on their backs at Bristol’s Ashton Gate.

“If it’s dry, I think Racing to win; if it’s wet, I think Exeter, because they have a better control at half-back and I think they have a bit of a set-piece upper hand over Racing,” he exclusively told this week’s Champions Rugby Show.

“I think if it’s drizzly or if it’s greasy, then Exeter will produce the goods; if it’s dry, I think Racing will score some brilliant tries. I’m excited by it.”

Roberts reckons another important factor in Saturday’s final is the match-up between Scotland team-mates Finn Russell, the Racing fly-half, and Stuart Hogg, Exeter’s full-back, both of whom are nominees for this year’s EPCR European Player of the Year.

“These guys have played together at Test level for many years,” said the Dragons centre, who has played 59 European games in 13 seasons.

“Stuart Hogg trying to anticipate Finn Russell’s kicking game is arguably the key to the match. If Stuart can do that, it will nullify a massive part of Racing’s armour.”

The former Cardiff Blues, Harlequins and Bath Rugby back is full of admiration for Russell, who has played in all eight of Racing’s Heineken Champions Cup games this season and whom Roberts has faced many times.

“You never knew when he was going to kick, pass or run,” the Welshman recalled. “You try and establish what opposition players are going to do next, but with Finn Russell you haven’t got a clue!

“How do you defend against him? You don’t give him space to run into and that arguably tightens the space between the defenders. But he has the ability and skillset to put the ball to width.”

Former Racing 92 centre Jamie Roberts believes the weather conditions will determine if his old club can win the Heineken Champions Cup for the first time on Saturday against Exeter Chiefs.