ESPN's rugby predictions: Games of the week, potential upsets & more

WATCH: Jordie Barrett's conversion from an impossible angle (0:10)

The All Blacks' Jordie Barrett showed off his impressive skills to convert a goal kick from a near impossible angle. (0:10)

We are getting towards the business end of the European season with just eight teams left standing in each of the Champions and Challenge Cups.

ESPN's experts predict which teams are set for a big weekend, which players will shine and where your attention should be trained across the quarterfinal action.

Player to watch

Champions Cup (Martyn Thomas): Garry Ringrose (Leinster). The Ireland centre made an important contribution to his country's Six Nations Grand Slam charge following his return from injury and he will hope to continue that form on the club stage as Saracens visit the Aviva Stadium for the weekend's final quarterfinal. He will be refreshed following a weekend off and the battle of the two midfields in Dublin should be intense, especially after Brad "Terminator" Barritt declared himself fit.

Challenge Cup (James Harrington): Adam Radwan (Newcastle). The winger needs just one more touchdown to overtake try machine Tom Varndell's record of 10 in a single tournament. Given Radwan, 20, has covered more metres (630), made more clean breaks (13) and beaten more defenders (45) than anyone else in this season's competition, it would be a brave punter who bet against him setting a new single-season mark. Connacht's Matt Healy is tracking Radwan closely, with eight tries -- a club record in the tournament.

Game of the weekend

Champions Cup: Scarlets vs. La Rochelle, Friday, 5.30 p.m.

Scarlets' reward for emerging from a tough Pool 5 is a mouth-watering home quarterfinal against La Rochelle. The west Walians are returning to the last eight for the first time sine 2007, while their visitors from France have progressed into the knockout stage at the very first attempt. Both sides like to play attacking, expansive rugby and there are exciting match-ups all over the pitch even though La Rochelle will be without injured No. 8 Victor Vito. Scarlets wing Steff Evans said this week that his teammates are "fizzing" ahead of the match, and the same goes for rugby fans all over the globe.

Challenge Cup: Edinburgh vs. Cardiff Blues, Saturday, 5.45 p.m.

Two of the PRO14's form sides meet for the first time in the Challenge Cup. What's not to like? This has all the hallmarks of a belter. Richard Cockerill's hosts have won six in a row, beating fellow quarterfinalists Connacht last time out courtesy of 16 points in 21 minutes from replacement Duncan Weir. The Blues, meanwhile, head to Scotland riding the wave of a five-match winning streak -- their best run since the 2009-10 season. Something has to give at Murrayfield. Watch out, too, for Edinburgh's Sam Hidalgo-Clyne, who needs just eight points to reach 200 in the competition.

Potential upset

Champions Cup: Clermont vs. Racing 92, Sunday, 1 p.m.

All four of this weekend's encounters look finely poised, but if you were looking to put money on an away win then Racing look the most attractive option. Clermont welcome the Parisians to central France with their season well and truly in the balance, and with the knowledge that they must win this year's competition to play in it next season. Racing have won three of their last four matches and lost narrowly at the Stade Marcel Michelin earlier this campaign.

Challenge Cup: Connacht vs. Gloucester, Saturday, 1 p.m.

A tight match is in store at Galway's Sportsground -- a fast start, too, as both sides have a habit of getting the Challenge Cup scoreboard ticking early on. The visitors have won the previous three European meetings between the two sides -- including a Challenge Cup quarterfinal. Gloucester fans will also be hoping that another recent historical quirk repeats itself -- Connacht reached the last eight in 2015 and 2016, losing each time to the eventual winners. But they have won nine of their last 10 at home in this competition.

Big weekend for...

Champions Cup: Saracens. Away trips don't come much tougher in European competition than Dublin, especially when the opposition is a Leinster side that provided the spine of Ireland's Grand Slam-winning team. The hosts will hope to harness the momentum created by Ireland's incredible spring, yet they would have hoped for an easier draw themselves having finished the pool stage as the competition's No. 1 seeds. Saracens are the back-to-back defending champions but with Billy Vunipola sidelined and Owen Farrell in a race to be fit, they will need a near-perfect performance to maintain their hopes of a three-peat.

Challenge Cup: Defending champions Stade Francais. Having scraped into the eighth and final quarterfinal slot -- as they did last year -- struggling Stade face a tough all-French trip to Pau. Simon Mannix's hosts have lost just once in 2018 in all competitions, and are apparently unbeatable at home. Top 14 survival may be uppermost in the Parisians' minds, but they won't want to give up their title without a fight ... especially as this year it comes with a Champions Cup qualification bonus.