The penultimate round of a short pool stage, and by Sunday evening we can expect to see several of the knockout places confirmed.
The paths to the final won't be clear until Round 4 however, with plenty of potential movement in the seedings across the second half of the pool stage.
Round 3 is a mirror image of Round 2, with Munster at home, and Ulster and Leinster on the road, while Connacht welcome Brive to the Sportsground in the Challenge Cup, looking to maintain their 100% record.
All four Irish provinces are in action on Saturday, starting at 1pm when Leinster travel to Gloucester, whom they hammered at the RDS in Round 2, before Munster host the Northampton Saints at Thomond Park at 3.15pm.
Out-of-form Ulster face a daunting challenge in the 5.30pm kick-off, away to the defending champions La Rochelle, with Connacht also in action against French opposition at the same time..
TV
Munster v Northampton Saints is live on RTÉ2 and RTÉ Player (Saturday, 3.15pm), with coverage getting under way at 2.30pm, with all other Champions Cup games live on BT Sport. Connacht v Brive (Saturday, 5.30pm) in the Challenge Cup will be streamed live on epcrugby.tv.
RADIO
Saturday Sport on RTÉ Radio 1 will have live commentary of Munster v Northampton Saints and La Rochelle v Ulster.
ONLINE
Follow our live blogs on rte.ie/sport and the RTÉ News app with match reports and reaction from around the grounds.
WEATHER
Leinster and Gloucester should have reasonable conditions for their meeting at Kingsholm, with early morning rain clearing up before kick-off, and temperatures of around 9C, although it will be windy at times.
There's less favourable weather in Limerick for Munster v Northampton, with plenty of rain forecast throughout the day, temperatures of around 5C, and winds of 25-30km/hr. There will be similar temperatures in Galway for Connacht v Brive in the Challenge Cup, with the possibility of rain the second half.
The worst of the weather will be in La Rochelle. While it will be a mild 14C, there's a lot of rain forecast, with winds hitting 40km/hr.
While Leinster will be big favourites to make it three wins out of three, a repeat of the 57-0 armchair ride they had when the sides met at the RDS last month seems quite unlikely.
Gloucester sent a shadow squad over to Dublin in December, prioritising their Christmas Eve Premiership meeting with Leicester Tigers. The last few weeks have been damaging to the English side, with Louis Rees-Zammit and Adam Hastings both ruled out with injuries.
Johnny Sexton, Tadhg Furlong and Charlie Ngatai will all miss out on the game for Leinster, with Ngatai the latest on the treatment table with a hamstring injury.
The province have been the standout performers in the opening rounds, with 99 points and 15 tries in just two games, while they also lead the tournament for clean breaks and metres gained in possession.
This will be just a second visit to Kingsholm for Leinster, where they were beaten 19-13 on their only previous trip in January 2007.
Gloucester: George Barton; Jonny May, Chris Harris, Seb Atkinson, Ollie Thorley; Santiago Carreras, Ben Meehan; Val Rapava Ruskin, George McGuigan, Kirill Gotovtsev; Freddie Clarke, Matías Alemanno; Ruan Ackermann, Lewis Ludlow (capt), Ben Morgan.
Replacements: Seb Blake, Harry Elrington, Ciaran Knight, Cameron Jordan, Jack Clement, Stephen Varney, Billy Twelvetrees, Tom Seabrook
Leinster: Hugo Keenan; Jordan Larmour, Garry Ringrose (capt), Jamie Osborne, Jimmy O'Brien; Ross Byrne, Jamison Gibson-Park; Andrew Porter, Dan Sheehan, Michael Ala’alatoa; Ross Molony, James Ryan; Ryan Baird, Josh van der Flier, Caelan Doris.
Replacements: Rónan Kelleher, Michael Milne, Cian Healy, Brian Deeny, Jack Conan, Nick McCarthy, Harry Byrne, Liam Turner.
Referee: Pierre Brousset (FFR)
Their meeting at Franklin's Garden's was far from a classic, Munster grinding out a 17-6 win which saw a second half containing zero points and four yellow cards, three of which went to Graham Rowntree's side.
The win in Northampton puts Munster in a solid position heading into the second half of the pool stage, and with their Ireland internationals returning they'll be favourites to take the spoils once again against a side that have nothing to show from their opening two games.
Munster's defence won them the game when the sides met in December, and that's been a common theme in recent outings, with the province conceding an average of one try, and just over 10 points per game in the last four weeks.
It's 11 years since Northampton last visited Limerick, and on that occasion Munster needed a Ronan O'Gara dropgoal to snatch a win, while they've won five of the seven meetings between the sides.
Phil Dowson's Northampton have enjoyed a lot of possession in the opening two games, carrying the ball 251 times, more than anyone in the competition. However they've also scored the least, with just 18 points across their opening two games.
Munster: Mike Haley; Calvin Nash, Antoine Frisch, Jack Crowley, Shane Daly; Joey Carbery, Craig Casey; Dave Kilcoyne, Niall Scannell, Roman Salanoa; Jean Kleyn, Tadhg Beirne; Jack O'Donoghue, Peter O'Mahony (capt), Gavin Coombes
Replacements: Scott Buckley, Josh Wycherley, John Ryan, John Hodnett, Alex Kendellen, Paddy Patterson, Rory Scannell, Liam Coombes.
Northampton Saints: George Furbank; Tommy Freeman, Matt Proctor, Rory Hutchinson, James Ramm; Fin Smith, Alex Mitchell; Alex Waller, Mikey Haywood, Paul Hill; David Ribbans, Alex Moon; Lukhan Salakaia-Loto, Courtney Lawes, Lewis Ludlam (capt).
Replacements: Robbie Smith, Ethan Waller, Alfie Petch, Alex Coles, Angus Scott-Young, Callum Braley, Fraser Dingwall, Courtnall Skosan
Referee: Tual Trainini (FFR)
Coming off the back of a run of five defeats in six games, Stade Marcel-Deflandre is one of the places you'd least like to be traveling.
Ulster's season is threating to fall apart, with Dan McFarland's side still reeling from their 38-29 defeat to Leinster in early December, that form continuing with a late defeat to Benetton in the URC last Saturday.
La Rochelle, meanwhile, had a statement win against Toulouse in the Top 14, beating Ugo Mola's side for the first time in nine attempts.
The defending champions were left slightly frustrated by their win against Ulster last month at the Aviva Stadium, winning 36-29 having been 29-0 and 36-7 in front at stages in the game, missing out on a bonus point in the process.
Ronan O'Gara's side still lead Pool B heading into the weekend, with nine points from their opening two games nudging them above Toulouse on points difference.
Worryingly for Ulster, only the Bulls have conceded more points in the opening two games.
La Rochelle: Brice Dulin; Teddy Thomas, UJ Seuteni, Jules Favre, Pierre Boudehent; Antoine Hastoy, Thomas Berjon; Thierry Paiva, Samuel Lagrange, Georges Henri Colombe; Ultan Dillane, Rémi Picquette; Remi Bourdeau, Paul Boudehent, Grégory Alldritt (capt).
Replacements: Quentin Lespiaucq Brettes, Reda Wardi, Joel Sclavi, Romain Sazy, Kyle Hatherell, Tawera Kerr Barlow, Pierre Popelin, Raymond Rhule
Ulster: Michael Lowry; Rob Lyttle, Stewart Moore, Luke Marshall, Jacob Stockdale; Ian Madigan, Nathan Doak; Rory Sutherland, Rob Herring, Jeff Toomaga-Allen; Alan O'Connor, Kieran Treadwell; Iain Henderson (capt), Nick Timoney, Duane Vermeulen.
Replacements: John Andrew, Eric O'Sullivan, Andy Warwick, Harry Sheridan, David McCann, Michael McDonald, Billy Burns, Ethan McIlroy.
Referee: Nika Amashukeli (GRU)
While Connacht's form has been hit or miss in the URC, Andy Friend's side have put themselves into a promising position in the Challenge Cup, with two wins from two games leaving them all but certain to be in the last 16 of the tournament.
Brive are eighth in the pool having also lost 41-0 at Cardiff Rugby in Round 1. However, they have enjoyed strong domestic form since their defeat to Connacht, winning all three of their Top 14 matches.
There's a strong connection between the two sides, with three ex-Connacht players in the Brive squad; Abraham Papali'i, Tietie Tuimauga and Sammy Arnold all leaving the Sportsground at the end of last season, although Arnold won't be involved this weekend.
Papali'i was red-carded when the sides met in France last moth, Connacht holding out for a 31-24 win, surviving a late scare.
Connacht: Mack Hansen; John Porch, Byron Ralston, Cathal Forde, Alex Wootton; Jack Carty (capt), Colm Reilly; Peter Dooley, Dave Heffernan, Finlay Bealham; Josh Murphy, Niall Murray; Cian Prendergast, Conor Oliver, Jarrad Butler.
Replacements: Dylan Tierney-Martin, Jordan Duggan, Jack Aungier, Leva Fifita, Ciaran Booth, Kieran Marmion, Tom Daly, Conor Fitzgerald.
Brive: Maxence Biasotto; Kevin Fabien, Wesley Douglas, Nico Lee (capt), Valentin Tirefort; Tom Raffy, Vasil Lobzhanidze; Hayden Thompson-Stringer, Vano Karkadze, Tietie Tuimauga; Andrés Zafra Tarazona, Oskar Konstantin Rixen; Matthieu Voisin, Sacha Gue, Abraham Papali'i.
Replacements: Aymeric Tronc, Nathan Fraissenon, Francisco Coria Marchetti, Joeli Matalaweru, Noé Bedou, Léo Carbonneau, Enzo Herve, Tom Danovaro.
Referee: Gianluca Gnecchi (FIR)
FULL CHAMPIONS CUP FIXTURES, RESULTS AND POOL TABLES
