Six Nations stars to watch in the European knockouts

Photo by Bob Bradford - CameraSport via Getty Images

As the Six Nations becomes more memory than momentous, so the business end of the northern hemisphere's rugby season rolls on unrelenting.

Many clubs in the three main northern leagues -- the English Premiership, Pro 14 and French Top 14 -- continue to jockey for play-off places, but in Europe the final fours are set. In the Champions Cup, Saracens, Munster, Leinster and Toulouse make up the final four, while La Rochelle, Sale, Clermont Auvergne and Harlequins are the contenders in the Challenge Cup.

Here are six players who starred in the 2019 Six Nations that you should watch out for in the closing stages of the race to the finals in Newcastle.

Tom Curry

England's long-standing problem at 7 is officially over. At least, it is officially over as long as Tom Curry stays fit. Such was the high standard he set throughout the Six Nations that it was no surprise to see Eddie Jones's best and most consistent forward performer among the nominees for player of the tournament -- along with six-try team-mate Jonny May and the Grand Slam-winning quartet of Josh Adams, Hadleigh Parkes, Liam Williams and eventual winner Alun Wyn Jones.

Curry's tournament stats are impressive enough: 97 tackles, the most of any player in the Six Nations, and a 90 percent tackle success rate with only eight missed in 360 minutes of high-intensity international rugby; five breakdown steals and two tries for good measure.

But statistics without context only tell the bones of the story. So let's add some flesh: Curry was a clear and present danger every minute he was on the field, a havoc cry at breakdown after breakdown, a constant threat with or without ball in hand. Hard to believe he's only 20, such was the maturity of the head on those shoulders.

If his form for country was not impressive enough, Curry is enjoying every minute of Sale's European campaign and was just as robust as ever in their 20-10 quarterfinal win over Connacht.

Peter O'Mahony

O'Mahony played every minute of every game for Ireland in the 2019 Six Nations and was a stand-out performer among a group of players that achieved a whole lot less than was expected after such a wonderful 2018.

The back row forward made six steals at the breakdown -- more than any other player in the tournament -- and that, alongside his 84% tackle rate, meant he could hold his head up high despite defeat to a dominant Wales in Cardiff as they wrestled the title away from last year's Grand Slam winners.

The former British & Irish Lions captain kept the good times rolling with Munster in the Champions Cup quarterfinals, although much of the credit for their win over Edinburgh had to go to Keith Earls who scored twice at a chilly Murrayfield including a late try to ensure a 17-13 victory.

But O'Mahony -- as he always seems to do -- went about his work in tenacious fashion and was the unsung hero of the piece, making 19 tackles and staying solid in the lineout. Ireland and Munster's ruckmaster should offer plenty more of the same in the semifinals.

James Ryan

The New Zealand rugby media can sometimes get a little carried away. So it was relatively easy to dismiss suggestions that Leinster's 22-year-old Ryan had ripped the World's Best Lock mantle from Brodie Retallick when Ireland beat New Zealand in Dublin in November.

Ryan is immensely talented and had played hugely well in that game, but this was World Cup-winner Brodie Retallick, who was the first second row ever to be named World Rugby Player of the Year in 2014, and who redefined the role of the modern lock forward. And who himself is just 27 years old.

Maybe, however, just maybe, Ryan offered more than a hint during the Six Nations that one day, sooner rather than later, he could be considered a challenger for the title the best lock in the world.

He definitely cemented a fast-growing reputation as one of Ireland's core players for years to come. It's hard to believe he only made his international debut in July 2017 and still does not have 20 caps to his name. He was involved in a lot of what was good about Ireland's forward play, and it's interesting that both Wales and England did manage to keep him relatively quiet.

Leinster are not short of second row quality but Ryan is exceptional and was immense against Edinburgh, making a whopping 27 tackles and more carries than anyone else on the pitch.

Romain Ntamack

There were few highlights for France in the 2019 Six Nations -- and Lyon's Felix Lambey cannot be included here for obvious reasons. Ntamack, 19, along with team-mate Antoine Dupont and Clermont's Damian Penaud, was one of few of Jacques Brunel's Bleus who did impress -- first at inside centre, where he started the tournament, and then at fly-half when Camille Lopez was dumped after the Calamity at Twickenham, despite only playing in that position for Toulouse only three times this season in the run-up to the match against Scotland.

All four of those players honorably mentioned above are under 25 -- proof, arguably, that France's youth policy could well even work if it ever were to be properly organised.

Ntamack stayed at No. 12 for Toulouse in their hugely entertaining quarterfinal against Racing 92 and was instrumental in Maxime Medard's crucial second-half try, shrugging off four tackles and playing the killer pass for Medard after receiving Lucas Tauzin's exquisite back-of-the-hand offload.

Jamie George

Dylan Hartley is England's hooker and captain, but given how well Jamie George is playing it looks difficult for him to even get back into Eddie Jones's team. George's Six Nations was a thing of simple joys -- effective scrummaging and solid lineout work, hard defence capped with a high 94% successful tackle rate and even a bit of attacking flair in the shape of a try and an assist against Italy.

The funny thing about George is he just seems to stick at it. He didn't even start a test match for England until his 18th cap, a world record in international rugby, but he is an Eddie Jones kind of guy and -- even though England fell short in the Six Nations -- George once again showed his head coach what there is to like about him.

If that battle for a World Cup place with Hartley -- who has been out injured -- is to emerge George's form with Saracens will be the catalytic factor, and, if the quarterfinals of the Champions Cup are anything to go by he is still going strong.

Against Glasgow Warriors he rumbled over for a try but also showed beautiful hands on more than one occasion as a bit of a playmaker for Sarries. Add to that his hard carrying, strong scrummage work and on-point lineout throws and you have a pretty special player.

Liam Williams

Before the Six Nations kicked off the big Welsh question was who should wear the starting fullback's shirt for Wales: Williams, or Leigh Halfpenny. The latter brought that unerring boot that would keep the scoreboard moving. The former... well... now we have been well-and-truly reminded just what the former brings.

The Saracens' man has surely made it difficult bordering on impossible for Warren Gatland to leave him out of the starting XV -- at the back or on the wing -- for the biggest Tests to come in 2019. He was man of the match against England after unerring displays against France and Italy, and then the final-round coup de grace to seal the Grand Slam against Ireland made it a near perfect tournament.

Then how Saracens, English rugby's only Champions Cup survivors, enjoyed him at his incisive best against Glasgow. He gave them the run-around by notching two excellent tries and was defensively astute particularly under the high ball.

BT Sport is the home of live coverage in the UK of the European Champions Cup and Challenge Cup.