The stadiums were closed to supporters on the opening weekend of the Six Nations - but the most important spectator was watching from the stands.

It is still not certain whether the Lions will be able to travel to South Africa this summer, but there is still hope the tour will go ahead in some form.

So who impressed on the opening weekend?

Steering the ship

Ireland's Johnny Sexton has proudly and admirably worn the number 10 jersey on the last two Lions tours, but the Irish stalwart will be nearing his 36th birthday when the Lions travel to South Africa, and Gatland will be considering alternatives.

The other two leading candidates at this stage went head-to-head at Twickenham on Saturday, and Finn Russell clearly came out on top in his Calcutta Cup battle with Owen Farrell.

Russell was influential as Scotland claimed their first victory at the home of English rugby since 1983, making seven carries and more metres off the boot (460) than any other player on the field. He also scored more than half of his side's points from the tee.

Farrell was surprisingly laboured as he struggled to release the hosts' potent backs, with former England full-back Mike Brown calling for the captain to be replaced by George Ford - who stands flatter to the gain line - in Italy.

Farrell has not played for Saracens this season and it's clear England's second highest points scorer of all time will improve as he regains his match sharpness, but it remains to be seen whether Gatland will favour his tried and tested pragmatic style or Russell's flair.

Meanwhile, Sexton's Ireland were beaten in Cardiff and he struggled to inject much impetus into their backline, albeit they played the majority of the game with 14 men. The experienced fly-half made more handling errors (two) than any other Irish player, while only Keith Earls and Conor Murray made fewer metres (37).

With 12 minutes remaining, and Ireland trailing 21-13, Sexton missed the chance to hand his side momentum by failing to reach touch from a penalty. His replacement Billy Burns suffered a similar fate in the final act, but this was far from vintage Sexton.

Opposite number Dan Biggar also had a quiet game as he missed the most tackles (three) in the Wales side.

The claim for captaincy

Alun Wyn Jones is a Wales colossus and his performance against Ireland was inspiring.

Unfortunately for Hugo Keenan, the veteran lock made three bone-crunching tackles, two of them on the Ireland full-back just minutes apart in the first half.

Playing his first game for two months after recovering from a knee injury, Jones made 25 tackles in total, with only Justin Tipuric completing more. Selection for the class of 2021 would be a fourth tour for the 35-year-old, but he continues to demonstrate his longevity at the highest level after lasting the full 80 minutes in Cardiff.

Scotland's Stuart Hogg will also be in the hat for captaincy after an excellent display from full-back. The visiting skipper made more metres (112) than any other player at Twickenham as he led his side to victory from the front.

He also broke the most tackles (eight) on the opening weekend.

Maro Itoje, yet to captain England but tipped to lead the Lions, was a shining light on a soggy night for England as he showed his commitment by charging down two Ali Price box kicks.

Farrell still remains a more than viable choice, as he played two of the three Tests against New Zealand in 2017 at number 12, so the experienced tourist provides another option even if he is not picked at fly-half.

Midfield contenders

In an ideal world, England's Manu Tuilagi and Wales' Jonathan Davies would pair up in midfield, but with both currently out injured, who could fill the void?

England handed a full debut to Ollie Lawrence at inside centre, but it was his opposite number and fellow debutant Cameron Redpath who impressed.

The former England Under-20 international, who rejected Eddie Jones' advances to choose Scotland, produced a performance that belied his years. Balanced running from 12 saw only Hogg make more metres for the Scots.

He's clearly short of Test match experiences, but former England scrum-half Matt Dawson said Redpath was "on the plane" if he "plays five games like he played on Saturday".

Meanwhile, experienced Wales and Lions wing George North moved inside to number 13 against Ireland. He also marked his 99th Wales cap with an impressive try as he spotted lock Iain Henderson in the green line before throwing the dummy and sprinting clear.

Ireland's Garry Ringrose did not deserve to finish on the losing side. Only team-mate and wing James Lowe made more metres than the outside centre (137) across all six teams, and his incisive lines and neat offloads (five) kept the Welsh defence honest, despite their numerical advantage after Peter O'Mahony was sent off.

The battle of the breakdown

The Scots never looked like losing control as they claimed that elusive win in England, and their tenacious performance was epitomised by lock Jonny Gray and flanker Hamish Watson.

The whole Scottish pack were relentless in their ball-carrying and work at the breakdown, forcing England to concede 15 penalties, but Gray made a team high two turnovers and 12 tackles, as Watson made 11.

Gray also carried the ball the most of any Scot (16), while Watson broke more tackles than any other visiting forward (four).

Billy Vunipola's most recent game was a friendly for Saracens against Ealing Trailfinders last month, and it showed at Twickenham as he failed to impose himself with ball in hand, while Tom Curry did not look quite as effective without his back-row partner Sam Underhill.

Both players have plenty of credit in the bank after playing a crucial role as England won the Six Nations and the Autumn Nations Cup in 2020, but they will be under the spotlight in the coming weeks.

In Cardiff, back row Tipuric was dominant at the breakdown and made an impressive weekend-high 29 tackles as Wales came from behind to beat Ireland.

The blue scrum cap seemed to be everywhere in the second half, and on this evidence, the two-time Lion looks likely to become a tourist again.

One to watch

As well as Redpath, another youngster who shone was Wales wing Louis Rees-Zammit.

The 20-year-old produced a finish in the corner with a touch of class as he rode Tadhg Furlong's tackle in mid-air before grounding the ball with an outstretched arm.

The Lions are actually well stacked up with rapid wingers from the last tour, but another couple of tries like that, and Gatland will be forced to take note.