RTÉ rugby analyst Donal Lenihan takes a look ahead to an exciting weekend of Champions Cup rugby for the Irish provinces.

All four teams are in action, with Munster first up as they take on French side Castres at the Stade Pierre-Antoine.

The sides come into the game having experienced very different starts to the competition.

Munster are chasing their third consecutive victory while Castres have lost both of their opening games.

On Friday morning Castres reported six cases of Covid-19 in their camp, but the Round 3 pool game still goes ahead as planned.

They will not have to make any changes to their matchday squad, with yesterday's team announcement taking the positive cases into account.

Lenihan - speaking before Castres announced the Covid cases - believes that the team selection shown by the French side indicates that they are already writing off the Champions Cup for the season and he expects a Munster win.

"I think Castres over the years have a rough association with this competition," he said on Morning Ireland.

"They're third in the Top 14 at the moment and beat Stade Francais last weekend but have made 14 changes to the team that plays Munster tonight.

"That would suggest that they’ve lost interest in the tournament but that said, there’s no love lost between these two teams.

"I expect Munster to win it but if they get sucked into a war of attrition, it could be as tight as the game against Castres the last time they met them, which the home side won 13-12.

"I’m expecting a Munster win but it will go down to the wire."

Connacht host Leicester at the Sportsground on Saturday afternoon and Lenihan believes that the Westerners will once again push the visitors all the way after their performance at Welford Road.

Andy Friend’s side were narrowly edged out in their clash with Leicester in December, losing 29-23, having led and controlled the game for large periods.

The game turned on a second-half yellow card for Finlay Bealham with Leicester able to make the advantage of an extra man count and while Lenihan expects another exciting encounter, he believes that Connacht will come unstuck again.

"Connacht play a fantastic brand of rugby as we know and Leicester are top of the Premiership," he said.

"They were unbeaten in their season up to last weekend when they lost on the road to Wasps.

"I think Connacht will approach this in a very positive manner, they stressed Leicester for a long time at Welford Road but their scrum let them down in the end.

"Leicester are obviously favourites to win this one but if they don’t get it right, Connacht have a chance.

"Overall I’d expect that the leaders of the Premiership will come out on top."

Leinster haven't played since 11 December

Leinster host Montpellier on Sunday where a win is needed and rustiness could be a factor for the home side, who haven’t played a game in over a month.

Lenihan believes that it will be a significant game not just for Leinster but for Ireland, with the Six Nations championship looming.

"I’m sure Andy Farrell, even more than Leo Cullen will be keeping his fingers crossed that this game goes ahead, which it looks like it will now," he said.

"Leinster haven’t played since 11 December and with the Six Nations only four weeks away, from an Ireland squad perspective, Farrell needs all those Leinster players performing.

"Montpellier were shocking in the opening game against Exeter when they sent over their seconds and I expect Leinster to come out on top.

"Leinster are going to be rusty and it might take a while to wear Montpellier down but I expect a Leinster win."

In the weekend’s other game Ulster are away to Northampton Sunday and for Lenihan, much depends on the team that Dan McFarland is able to put out.

Ulster have several injury concerns and both Stuart McCloskey (hamstring) and Iain Henderson (ankle) are doubts.

"It’s a tough game for Ulster even though they did claim a great win in Belfast a couple of weeks ago.

"But if McCloskey and Henderson are out of the Ulster team then I think Northampton might have too much for Ulster."

Listen to the RTÉ Rugby podcast on Apple Podcasts, Soundcloud, Spotify or wherever you get your podcasts.

Follow Castres v Munster (Friday, 8pm), Connacht v Leicester (Saturday, 3.15pm), Leinster v Montpellier (Sunday, 1pm) and Northampton v Ulster (Sunday, 3.15pm) via our live blogs on rte.ie/sport or on the RTÉ News App, or listen to live radio coverage of Castres v Munster and Connacht v Leicester on RTÉ Radio 1 Extra and RTÉ Radio 1.