Some of the best clubs in world rugby have had their chance to warm up and work out the kinks.

Now, it's time for the real tests.

The Heineken Champions Cup - Europe's top yearly club rugby competition - returns for another go-round this weekend with Round 1.

Throughout the course of this year's schedule, FloRugby will provide a weekly look at the tests and showdowns to check out, from the four pool rounds to the knockouts to May's final in Dublin.

There's a new country being represented in the Champions Cup (and a new defending champion, as well) for the first time this season, and with competition truly branching out into a new era and welcoming clubs outside of the European continent - more on that below - it also throws a wrench in the predictability of the tournament itself going forward.

Translation: The next few months are going to get a bit wild.

Here's a look at the matches to watch this week, as the Heineken Champions Cup gets under way across the globe, with all matches being streamed live on FloRugby.

NOTE: Kickoff times are listed in Eastern time and are subject to change.

La Rochelle Vs. Northampton

The ultimate rugby underdog story of the past decade, La Rochelle - once a yo-yo club that bounced around between France's top divisions - has rocketed its way to the top of the continent in the most thrilling run in the western French coast's history. 

Since Ireland and Munster legend Ronan O'Gara overtook the reins on the touchline for the Privateers in 2019, he's since taken La Rochelle to unforeseen heights, with the club finishing as the runner-up in the Champions Cup (2020-2021) and winning the whole thing last season against a club from O'Gara's homeland, Leinster, in the final in Marseille in May. 

The title defense starts now, and La Rochelle, which has had a reputation of playing the plucky underdog role in the past few seasons, is in the unfamiliar spot of being the team everyone else is chasing. 

Never a dominant force in the Top 14 (the Champions Cup win was La Rochelle's first major piece of silverware in its history, including domestic league titles), the Privateers only finished fifth last year back in the French top division during its magical European run. 

It makes their current standing of fourth on 31 points through 12 matches in the Top 14 a bit less concerning. 

Pool B play kicks off against Northampton at the Stade Marcel Deflandre, with the Saints currently in the middle of the road at sixth in the table amid an unusual Premiership Rugby season. 

The English league started the year with 13 teams but lost two, after Wasps and Worcester Warriors both entered administration this fall due to financial issues, expunging their records and relegating them automatically to the second-tier RFU Championship for next season. 

La Rochelle is on a nine-match unbeaten run in European play, making it the favorite in Round 1 at home, but keep an eye on some difference makers in Saints colors, including Fijian veteran Sam Matavesi at hooker and lock Alex Coles, who made his England debut in the Autumn Nations Series against Argentina.

Bulls Vs. Lyon

Want to see some history in the Challenge Cup this weekend? Look no further. 

Lyon travels to Pretoria, South Africa, to play the Bulls at one of the most iconic venues in international rugby - Loftus Versfeld - to which it'll now play host Saturday to the first Champions Cup match ever played outside of Europe. The competition began in 1995-1996. 

This year's Champions Cup (for which South African clubs now are eligible for the first time after four teams from there joined the United Rugby Championship field a year ago) will be a massive moment and chance for South African clubs to prove themselves in one of the world's most prestigious events. 

For the Bulls, who were the only South African side to ever win Super Rugby during the country's involvement in that competition from 1996-2020, they already carry the standing and banner as South Africa's most successful club in the professional era, giving them, theoretically, an upper hand on the rest of the competition, as it already knows how to win silverware in an outside league against foreign opposition. 

Unbeaten at home so far this season ??#TrueToTheBlue @Vodacom #URC pic.twitter.com/3GEUOPhzVR

— Official Blue Bulls (@BlueBullsRugby) December 5, 2022

However, the Bulls' first foe in its Champions Cup history is a doozy: French club Lyon, the winner of last year's second-tier Challenge Cup - therefore securing it automatic qualification into this year's Champions Cup - may have only finished ninth domestically in last season's Top 14, but its simultaneous continental run was dominant. 

The Wolves secured top seed for the knockouts following a 4-0 pool stage and rolled through the elimination games, until the Wolves beat French rival Toulon in the final for their first top-tier or European crown since winning the French domestic league title in 1933. 

Lyon No. 8 and former Springbok Arno Botha will be a familiar face in Pretoria, as he played in two separate stints for the Bulls during the 2010s, but the Bulls will hope that doesn't distract them, as their all-South African squad features numerous national team names, including captain Marcell Coetzee and dynamic winger Kurt-Lee Arendse. 

Sale Sharks Vs. Ulster

The two-time Challenge Cup champion Sharks have yet to ever make it past the quarterfinals in the Champions Cup, and after back-to-back trips to the final eight in the past two seasons, coach Paul Deacon's men are chomping at the bit to finally get over the hump and take the Champions Cup trophy back to England. 

By the way they've been looking this year in the Premiership, it very well could be the season for the Sharks to do it. 

Only behind table-topper Saracens at the moment through nine matches and half of the league calendar, South African fly-half Robert du Preez is scoring points for fun with the Premiership's highest tally (87) by far, while Scottish-born (though England youth international) 21-year-old winger Tom Roebuck has emerged as a consistent starter for the Sharks over the past two seasons, scoring four tries thus far in the Premiership campaign. 

Additionally, with the Premiership's best defense (191 points allowed, 21.2 per match), it's a one-two punch that is too powerful of a combination for most teams to handle. 

Perhaps Ulster could become one of those teams, too. 

Hailing from Belfast, the Irish club returned to the Champions Cup and made it back to the knockout rounds last season after missing out on qualification for the competition in 2020-2021, the only time in its existence it missed out on Europe's top continental rugby tournament. 

Currently fourth in the United Rugby Championship, forming an Ireland-South Africa sandwich with leaders Leinster and second- and third-place clubs the Bulls and Stormers, Ulster has kept things consistent, with its only two defeats coming at the hands of Leinster - including one last Saturday. 

But with a squad featuring eight players that made the Irish Autumn Nations Series squad (a squad that's currently ranked No. 1 in the world, by the way), Ulster is always bound to bring quality and should be a proper test to the Sharks in Pool B.