Leinster are the best-placed of the Irish provinces in Europe, while Munster and Ulster are in must-win territory ahead of the back-to-back Champions Cup fixtures. 

Connacht, meanwhile, are two from two in their Challenge Cup pool. 

Exeter v Leinster

Leinster and Exeter both carry 100% records into Sunday’s Sandy Park tie (5.30pm) so something’s got to give.

The three-time European champions beat Montpellier, 24-17, in the opening round before effectively ending Glasgow’s interest with a 34-18 victory in Scotstoun, both bonus-point wins.

Similarly, Exeter also accounted for the Scottish outfit at home, 24-15, before beating the Top 14 side in France – the 27-24 victory a serious statement of intent.

The head-to-head, however, is in the visitors’ favour with Leinster having won both their previous European encounters back in 2012/13.

Johnny Sexton led from the front against Glasgow

Since then, the Chiefs have won the Premiership for the first time (2017) and currently top the English table with eight wins from 10.

It’s the sort of challenge that Leo Cullen’s men, second in Conference B of the Guinness Pro14, will relish.

That placing in itself is a testament to where the province is at the moment.

Like Exeter, they have won 10 times this season in all competitions. But that covers spells where their full contingent of international players were unavailable, injured or rested.

It’s quite impressive how they have gone about their business: with a minimum of fuss, absorbing the loss of key players without any major difficulties.  

They’ve lost just two games, with one of those coming on the ill-fated trip to South Africa.

The latest reports suggest that Robbie Henshaw will be in contention to start after recovering from a hamstring injury sustained in the build up to the Argentina Test.

He could be joined by Garry Ringrose, the Ireland centre also making an impression on his seasonal debut last week.

Their health is so rude that Cullen has judged he can do without new signing James Lowe for the Pool 3 tie.

The New Zealand wing scored twice in an impressive debut against Benetton last weekend but he was not registered for the competition, with antipodeans Scott Fardy and Jamison Gibson-Park retaining the two 'overseas player' places in the squad.

Forwards Dan Leavy and James Ryan will be assessed ahead of the game.

Rob Baxter’s charges are on a nine-game winning streak and Leinster scrum-half Luke McGrath has called them the "form team in Europe".

The most recent of those games was a six-try 42-29 win over local rivals Bath, while Saracens and Harlequins also fell under the wheels.

"Leinster are a great side and they always seem to turn up for the big games," said England winger Jack Nowell, who last week returned from a face injury after an eight-week lay-off.

Munster v Leicester

Two sides steeped in European history go toe-to-toe on Saturday evening at Thomond Park (7.45pm).

The Pool 4 clash will be the ninth European meeting between the teams, whose intertwining paths in this competition are one of the tournament’s most enduring stories.

The two two-time winners also met at this stage last season with each claiming one win, Munster secured a 38-0 victory at home before losing to a late penalty in the reverse fixture.

Munster dominated Leicester in last season's corresponding fixture

This particular group has failed to fire so far and both Munster and the Tigers have six points.

Munster, then under Johan Erasmus, drew 17-17 away at Castres before digging deep to beating Racing 14-7 in Limerick.

Leicester, sixth in the Premiership, lost away in Paris on the opening day, 22-18, but hammered Castres at home, 54-29.

It is acknowledged that Munster’s situation, where new coach Johann van Graan took over after a prolonged process, is far from ideal.

In addition, contract talks between two of the province’s stars, captain Peter O’Mahony and CJ Stander, are in progress. The vista of losing the two Ireland back-rowers doesn’t bear thinking about.

"They’re the only team in Europe to come here to Thomond Park and win twice," said O’Mahony about the visitors.

"I don’t think fear factor will be an issue for them."

Domestically, Munster sit second in Conference A with seven wins from ten rounds.

They must do without Keith Earls, who has been out of action since the start of November. Chris Farrell, Simon Zebo and Tyler Bleyendaal may also miss out. 

Van Graan, at 36-years-old and taking on his first major front-line job, is in the deep end.

Leicester, under former Leinster boss Matt O’Connor, have lost their last two Premiership games.

The Welford Road side have also had to recall prop Michele Rizzo from Edinburgh after Ellis Genge was injured in the weekend defeat to Wasps.

Experienced Tigers scrum-half Ben Youngs says: "It is going to have that Test-match intensity and feel to it."

Harlequins v Ulster

Ulster, with four points from their opening games, are hanging on in Pool 1 ahead of Sunday’s visit to a sold-out Stoop to face Harlequins (1pm).

A chastening 41-17 defeat in La Rochelle last time out really emphasised how tough qualification will be for the 1999 champions.

They did manage to record a win in round one, 19-9 over Wasps, but they must improve on their recent Pro14 performances, including a 32-32 draw at Dragons, a game where they conceded five tries.

Ulster needed a late try to salvage a draw against the Dragons

The absence of Paddy Jackson and the signings of Marty Moore and Jordi Murphy for next season seems to give weight to the theory that this season will be a bridge towards 2018/19.

Les Kiss’ men are third in Conference B with seven wins, two losses and a draw.

He said: "I think in the last three games, the set piece has failed us at different times. What does that mean? Does it mean you will lose the game?

"We have yielded 11 tries in our last three games, and that should not define the season, we just have to find a way to improve the little things we would like to." 

Domestically Harlequins are also having a mixed season. The London side sit seventh in the Aviva table, having won five and lost five.

Last weekend’s last-gasp 20-19 win over Saracens ended a two-game losing run and any win over the European champs obviously bodes well.

But their form in the Champions Cup is non-existent: a losing bonus point at home to La Rochelle, 27-34, is all they have to show for their efforts.

Their round-two tie against Wasps ended in a 41-10 loss.

Brive v Connacht

Connacht will aim to make it three from three in their Challenge Cup Pool 5 clash away to Brive on Saturday (8pm).

Kieran Keane’s men have already accounted for Oyonnax, 43-15, and Worcester, 15-8, while this weekend’s opponents have beaten their French counterparts and lost to Warriors in their two games to date.

Connacht didn't even manage to get a bonus point in Italy

However, Connacht’s recent form is a cause for concern and after their recent 24-10 loss to Zebre, Keane told RTÉ Sport: "We didn’t have a lot of energy in the tank or willingness. Everything broke down on us.

"Some individuals didn’t endear themselves too well."

Brive are third from bottom of the Top 14.

Listen to exclusive Champions Cup radio commentary of Exeter v Leinster on RTÉ Radio One’s Sunday Sport programme (kick-off 5.30pm).

Live updates of Munster v Leicester on Saturday (7.35pm) and Sunday’s games featuring Harlequins v Ulster (1pm) and Exeter v Leinster (5.30pm) on RTÉ.ie and the News Now app.