The Champions Cup begins in earnest this weekend as all four Irish provinces open their respective campaigns against French opposition.

Leinster and Connacht will be buoyed by their interprovincial victories last weekend, while Ulster and Munster have little time to lick their wounds with daunting away trips to Bordueaux-Begles and Top 14 champions Racing 92 respectively.

Pool 4 - Leinster v Castres, RDS, Saturday 3.15pm

Leinster supporters will hope for an improvement after five pool losses last season and the early signs are positive.

The Garry Ringrose/Robbie Henshaw centre partnership got its first run-out last weekend, Johnny Sexton has collected the last two man-of-the-match awards while the scrum has looked comfortable for the most part.

The imminent of return of Seán O'Brien is another fillip in a back row brimming with options.

Castres are struggling in the Top 14, with more defeats than victories after their opening eight games and are coming into the game on the back of two successive losses.

The French side have won just once in six meetings with Leinster and with home advantage, Leo Cullen’s side will know a victory is imperative to harbour ambitions of a place in the knock-out stages.

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Pool 2 - Connacht v Toulouse, The Sportsground, Saturday 5.35pm

The Sportsground will welcome the four-time European champions in a fixture that holds a special place in the hearts of the Connacht supporters.

The French kingpins were the first visitors to Galway in the top tier of European competition five years ago and few will forget the Westerners' shock 16-14 win at the Stade Ernest-Wallon just two years later.

A win on Saturday would not cause the same ripples this time around, as the Pro12 champions have recovered from a disappointing league start to record two wins on the trot, including a very impressive victory against bogey side Ulster last time out.

Their attack looked far more clinical and with Bundee Aki punching holes in the defensive line, Toulouse could be in danger of losing a fifth Champions Cup defeat on the spin after finishing bottom of their pool last season with just a solitary victory.

They pushed Clermont to four points away from home last weekend as they seek a fourth European win over Connacht.

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Pool 5 - Bordeaux-Begles v Ulster, Stade Chaban-Delmas, Sunday 1pm

Billed as the Iain Madigan v Paddy Jackson show from an Irish perspective, Ulster will have their work cut out to leave France with a positive result at the weekend.  

Madigan could only watch on as Lionel Beuaxis kicked five penalties and a conversion in Bordeaux's two-point victory over Brive last weekend, but will be hopeful of pitting his wits against the player who proved an accomplished replacement for Johnny Sexton in South Africa.

Director of Rugby Les Kiss admitted his side were poor in the defeat to Connacht and were guilty of far too many turnovers at the breakdown.

With Jared Payne at full-back and the returning Tommy Bowe on the wing, their backline looks full of danger. It is the scrum that faces more scrutiny and with Bordeuax moving nicely at the start of the season, this will be a stern test for their forwards

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Pool 1 - Racing 92 v Munster, Stade Yves-Du-Manoir, Sunday, 3.15pm

Rassie Erasmus has had little time to pore over the defeat at the Aviva Stadium against Leinster, with a visit to Top 14 champions Racing to look forward to on Sunday afternoon.

The presence of Ronan O’Gara, Munster’s all-time top scorer in the competition and two-time winner, will provide an interesting sub-plot while Racing will be keen to get back to matters on the pitch after the recent TUE revelations.

Pressing for Munster is to get the maximum from their callow backline. A facile win over Zebre was another impressive outing from Darren Sweetnam, but defensively the former Cork hurler found the going much tougher against Leinster.

Even greater responsibility is falling on Tyler Bleyendaal with the likes of Sweetnam, Rory Scannell and Ronan O’Mahony finding their feet at this level.

Racing have had a mixed start to their title defence, four wins from eight games, their latest a seven-point win over Stade Francais last time out.

The French side topped their pool last year and will be bidding to go one step further after losing to Saracens in the decider.

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