The night before four of their countryman take to the field in Rotorua for the unofficial ‘fourth test’ between the British and Irish Lions and the Maori All Blacks, the Wales national team begin their summer campaign against Tonga at Eden Park in Auckland, the venue of their heart-breaking RWC 2015 semi-final defeat to France.

Friday's match is the first part of a double-header, followed by New Zealand’s meeting with Samoa, to hopefully set the tone for what should be another fascinating weekend of international rugby.

While the All Blacks do not stand to gain any rating points for victory over Samoa, due to the 13-and-a-half point gap between themselves and their 14th-ranked opponents, Wales will improve their current rating by a maximum of nine-hundredths of a point if they begin their tour of the southern hemisphere on a winning note. Caretaker coach Robin McBryde then takes his squad to Samoa to face them in Apia on 23 June.

WALES CALL UPON UNCAPPED TRIO

The slender reward on offer for victory over Tonga would not be enough to lift Wales any higher than their current position of seventh, although with less than two points covering four teams in and around them in the rankings, a defeat could see them drop to as low as ninth if other results don’t go their way.

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Uncapped trio Steff Evans, Seb Davies and Thomas Young have been named in the Wales starting line-up, while another six players could make their test debuts off the bench.

Tonga get their first run-out since November, when they recorded an unprecedented three wins on the bounce against Italy, USA and Spain, with the Wales game serving as a warm-up to the World Rugby Pacific Nations Cup, where the Ikale Tahi need positive results against Samoa and Fiji to have any hope of claiming the Oceania 1 or Oceania 2 qualification places at RWC 2019.

Auckland fly-half Latiume Fosita (pictured) will start in front of his home crowd in a strong-looking Tongan team captained by outside-centre Siale Piutau.

Should they register their first victory over Wales in a full-blown international at the eighth attempt, Tonga would move up to 12th in the world at Georgia’s expense unless the Lelos beat USA by more than 15 points and the Ikale Tahi don’t match that margin.

HISTORIC HIGH FOR SCOTLAND?

While Scotland victory over Wales at the World Rugby U20 Championship guaranteed them their best-ever finish in the premier age-grade competition, the senior team also have a new milestone within their sights – a place in the top four of the World Rugby Rankings.

To achieve this, Gregor Townsend’s side, showing eight changes from the one that beat Italy 34-12 in Singapore last weekend, would need to overturn their recent narrow losses to Australia in Sydney on Saturday and win by more than 15 points. Third place is even up for grabs if they win by more than 15 points and Ireland fail to beat Japan in Shizuoka.

Like second-ranked England, the Wallabies cannot move any higher than their present position and will stay third even if they win well and Argentina beat Eddie Jones' troops by more than 15 points in Saturday’s eagerly-awaited rematch in Sante Fe. However, Australia can close the gap in the rankings to just half a point in such a scenario, as they would move up to 86.78 points with England down to 87.28.

Australia coach Michael Cheika has opted for continuity with just the one enforced change from the XV that defeated Fiji, Eto Nabuli coming in to make his debut on the left wing, in place of the injured Henry Speight.

With three of the last five fixtures between the nations settled by a single point, most famously at Twickenham in the quarter-final of RWC 2015, it is a game that's simply too close to call.

Meanwhile, Ireland can leapfrog Australia into third if they win well against Japan and their Celtic cousins Scotland do the business against the Wallabies.

FIFTH PLACE FILLIP FOR FRANCE?

At least half a point will be added to South Africa’s rating if they are able to beat France for the second weekend running and take the three-test series with one match to go. That will only be enough to lift them into the world’s top four if Ireland suffer the same fate as the Welsh tourists of 2013 and lose to the Brave Blossoms. Any form of win for France combined with defeat for Scotland would catapult Guy Noves’ side up three places to fifth.

Argentina let a golden opportunity to improve their ranking slip when they conceded a last-minute try to England, scored by debutant Denny Solomona, in San Juan. But they get another chance to put one over their Pool C opponents at RWC 2019 this Saturday, and potentially improve their rating by as much as 2.59 points.

If the results of the sides immediately above them in the rankings go according to the formbook, with a win for Wales and defeat for France, Los Pumas will replace Les Bleus in eighth.

BRAVE BLOSSOMS EYE RETURN TO TOP 10

A victorious Fiji will only lose their place in the world’s top 10 to Japan if the Brave Blossoms pull off a result nearly as big as their RWC 2015 triumph over South Africa and beat Ireland by more than 15 points. Fiji take on Italy in Suva three years on from their 25-14 victory over the Azzurri there. A rise of three places to 12th is potentially within Italy’s grasp if they were to win in the Fijian capital for the first time in 20 years.

Romania will take their rating past the 70-point mark if they inflict another defeat on Canada, however there is still too much daylight between themselves and 15th-placed Italy for the Oaks to improve their position. Likewise, the USA Eagles can only supplant Romania in 16th if they beat Georgia by more than 15 points and the Oaks fall by a similar margin against Canada.

Aaron Carpenter will become Canada’s most capped player if he plays against Romania on Saturday, and the back-row would dearly love to mark the occasion with a morale-boosting victory. It’s a long shot, as other results would need to go their way, but it is possible for the Canucks to get back into the world’s top 20 with a big win over Romania.

As the Nations Cup reaches its denouement, tournament hosts Uruguay are 80 minutes away from claiming their first-ever title and possibly a three-place rise in the rankings. To have any chance of doing so, they'd need to follow up Wednesday’s 32-29 comeback win over higher-ranked Russia with victory over Spain in Montevideo. Namibia can prevent Los Teros moving ahead of them in the rankings, though, if they beat Russia by a significant margin in the only other Nations Cup match to count towards the rankings.

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Mexico know that a draw against the Cayman Islands will secure them top spot in the north zone of the Rugby Americas North Championship 2017 and a play-off against south zone winners Guyana for the overall title.

A big victory in Georgetown against their hosts would come with a 1.5-point reward and a jump of seven places to 43rd, while victory for the Cayman Islands would lift them at least one place to 56th.