France stunned Ireland in Dublin to become Six Nations title favourites, Scotland held off a late Wales comeback, and England comfortably saw off Italy to keep their title chances alive.
Here's our round-up of the big talking points from the fourth round of fixtures in the 2025 championship.
France delivered one of their greatest Six Nations performances to thrash holders Ireland 42-27 in Dublin.
But rather than experiencing pure euphoria after a near-perfect performance, the French camp vented their anger after their talisman Antoine Dupont ruptured cruciate ligaments in his knee.
The 28-year-old scrum-half was forced off in the first half after Ireland lock Tadhg Beirne fell on to his leg at a ruck.
France head coach Fabien Galthie referred Ireland pair Beirne and Andrew Porter to the citing commissioner for possible retrospective punishment, which was later dismissed.
"There was zero malice in it," former Ireland wing Simon Zebo, a former Munster team-mate of Beirne, told BBC's Six Nations Rugby Special.
"Tadhg is a clean player and wouldn't wish any bad intent on anyone. The only thing is, it is not a great image.
"There is a lot of power coming into that ruck and it looks worse than it is. No-one wants to see him [Dupont] out of the game as he is the best player in the world."
Dupont, who was replaced by Maxime Lucu, provided seven assists and scored two tries before his tournament was cut short.
Victory over Scotland at Stade de France will likely secure a first title in three years, with arguably the best player in the world now potentially having to lift the trophy in a tracksuit.
Ireland's goal this campaign was to become the first side in Six Nations history to win three successive outright titles.
Victories over England, Scotland and Wales secured the Triple Crown, and put interim Ireland head coach Simon Easterby two games from a Grand Slam.
But a ruthless France scored five tries in a clinical display to outclass Ireland on their own patch.
Their tally of 26 tries after four matches is just three shy of the overall championship record set by England in 2001.
Following a surprise defeat by England in round two, Galthie has opted for a 7-1 bench spilt, which helped inflict an 11-try hammering of Italy.
Ireland - like Italy in Rome - struggled once Galthie unloaded this powerful bench early in the second half, resulting in the most points the French have ever scored in Dublin.
"I have never seen an Irish pack dominated so much," former Wales back Jonathan Davies told BBC's Six Nations Rugby Special.
"Ireland have been very good and competed with everyone in the world, especially up front. The bench came on and blasted them."
France even ended up with flanker Oscar Jegou playing at centre for a large chunk of the second half after Pierre-Louis Barassi went off injured.
The 21-year-old impressed out of position and put in a crunching covering crunching hit on Ireland fly-half Sam Prendergast to show incredible versatility.
Scotland bounced back from a disappointing loss to England to register a 35-29 victory over Wales at Murrayfield.
Full-back Blair Kinghorn enhanced his British and Irish Lions credentials with two tries in a player-of-the-match performance.
Gregor Townsend's side looked to be cruising to a comfortable victory only for the the visitors to threaten a late comeback by grabbing three unanswered tries.
Townsend's side need a miracle in the final round to win the championship but can take heart from their 2021 triumph in Paris when a last-gasp Duhan van der Merwe try sealed victory.
"I know it was in Covid but Scotland have gone and won in Paris," former Scotland number eight Johnnie Beattie told BBC's Rugby Union Weekly.
"That means there is a belief they can do it, but it is a different beast than taking on Wales in terms of organisation, strategy and physicality.
"If France have an average game and Scotland fire out shots and are clinical then we can challenge them."
If England or Ireland are going to win the title, they will need a favour from their Celtic rivals, and Scotland's dangerous backs might just fancy their chances in an open game.
Despite promises of fast-paced, attacking rugby by head coach Steve Borthwick, England reverted back to their kicking game in their third-round win over Scotland.
But on Sunday, the hosts delivered by scoring seven tries in a comfortable 47-24 victory over Italy at Allianz Stadium to stay in the title hunt.
Borthwick's side kicked the least amount of times from hand (31) this championship - five times fewer than last time out against Scotland - and made the most carries so far this campaign (145) - 67 more times than in their previous outing.
Central to England's attack this championship has been Bath centre Ollie Lawrence, who went off early on with an Achilles injury and is set to undergo scans to determine the severity of his lay-off.
"He was really coming into his own in this England set-up and playing well for Bath, which is really frustrating for him," Zebo added.
"He is in sensational form this year and would have a very good chance of making the [British and Irish Lions] plane to Australia in the summer."
England are undefeated since their opening round defeat by Ireland, but will need Scotland to defeat France in Paris if they are to snatch the title with a win over Wales.
Wales' defeat by Scotland registered their 16th loss in a row.
Late scores helped improve what was starting to become a heavy scoreline at Murrayfield as Wales continue to show fighting spirit under interim head coach Matt Sherratt
With the clock in the red, Max Llewellyn's try was converted by Jarrod Evans as Wales recovered from 27 points down to grab two losing bonus points for scoring four tries and finishing within a score.
They host England on Saturday and will hope the emotion of their home crowd can help them cause an upset.
"Everything points to England as they are a better side and Wales are on a disastrous losing run," Davies added.
"It is the last game and it is in Cardiff. It will be crazy there. The Welsh boys will get up for it.
"If they get to the intensity they did against Ireland and play like they did, then Wales will be in with a shout."