Cian Healy suffered an injury scare on the eve of Ireland’s World Cup squad announcement during an unconvincing 17-13 success over Samoa in rain-soaked Bayonne.

Veteran prop Healy was helped from the field in obvious discomfort less than 24 hours before Andy Farrell names his final 33-man selection for the upcoming tournament in France.

Despite Jimmy O’Brien’s early try, Ireland trailed at the break in their final warm-up fixture, before battling back to scrape a 13th straight win thanks to further scores from Conor Murray and Rob Herring.

Yet the result at a sold-out Stade Jean Dauger could come at significant cost after Healy, who departed just 21 minutes into his 126th Test outing, added to Ireland’s front-row concerns.

Farrell’s planning has already been complicated by ongoing injury issues for Healy’s fellow loosehead Dave Kilcoyne and hookers Dan Sheehan and Ronan Kelleher, although he expects the trio to be available in the coming weeks.

The head coach, whose side begin the World Cup on September 9 against Romania in Bordeaux, was also forced into a change ahead of kick-off as a “niggle” for wing Keith Earls afforded a chance to Jacob Stockdale.

Heavy rain and forecasts of thunderstorms in south-west France did not deter a capacity crowd from turning out, with the slippery conditions contributing to a series of fumbles.

A fine Murray tackle denied Samoa an early lead before Jack Crowley’s pinpoint cross-field kick allowed Mack Hansen to gallop down the right wing and give full-back O’Brien a simple finish for his maiden Test try.

Ireland have unsettling memories of this stadium, having endured a bruising affair – dubbed the Battle of Bayonne – against the host club ahead of the 2007 World Cup.

Physicality was at the forefront of this encounter and Farrell’s men suffered a setback when the hobbling Healy was assisted off the pitch by medical staff and replaced by Jeremy Loughman.

Unfamiliar in white shirts and blue shirts, Ireland’s mix-and-match line-up were struggling to find their rhythm.

They ended the half 10-7 behind after Duncan Paia’aua intercepted a Stuart McCloskey pass inside his own half to brilliantly race clear and dive over, before Lima Sopoaga added the conversion and a subsequent penalty.

Samoa, who will be England’s final pool-stage opponents in early October, were facing a tier one nation for only the second time since losing 47-5 to Ireland at the 2019 World Cup.

A second penalty from former Wasps fly-half Sopoaga stretched their lead early in the second period before Stockdale’s kick over the top was gleefully dotted down by the diving Murray, albeit Crowley’s wayward conversion left Ireland a point behind.

The world’s top-ranked side finally regained the lead 17 minutes from time when replacement hooker Herring bulldozed over from a line-out maul.

Crowley’s conversion attempt was charged down before James Ryan was held up on the line to keep the contest firmly in the balance.

Roared on by the mostly-French crowd, Samoa refused to roll over and continued to cause problems.

Yet, on a day when Fiji stunned England at Twickenham, they ultimately fell short of producing a further major shock as Ireland survived a significant wake-up call which could yet prove expensive due to Healy’s premature exit.

Jac Morgan will captain Wales on Saturday in what is effectively the first of three World Cup leadership auditions.

The 23-year-old Ospreys flanker takes charge for Wales’ opening tournament warm-up game against England in Cardiff.

Wales then go to Twickenham seven days later before hosting reigning world champions South Africa – and there is likely to be a different skipper each time as head coach Warren Gatland considers his options.

Hooker Dewi Lake, fly-half Dan Biggar, plus locks Adam Beard and Will Rowlands are also among realistic captaincy candidates.

Should Morgan or 24-year-old hooker Lake be handed the World Cup reins, it would echo Gatland appointing Sam Warburton as skipper for the 2011 tournament, when he was just 22.

“We’ve named Jac as captain for this match, and it is a great honour for him to be leading his country,” Gatland said.

“We will be looking at probably having a different captain for each of the matches as we give as many as possible in the squad an opportunity to impress, but also mindful about potential combinations as we get closer to naming the World Cup squad.”

Gatland is set to name his final 33-strong World Cup squad later this month, and there are early chances in the spotlight for an uncapped trio of Max Llewellyn, Corey Domachowski and Keiron Assiratti, who all start against England.

And former England prop Henry Thomas, who qualifies for Wales through his father and has been able to switch countries under new World Rugby regulations, is among the replacements along with fellow uncapped forward Taine Plumtree.

Since the start of last year, players can switch to their country of birth – or their parents’ or grandparents’ birth – provided a minimum period of three years has elapsed since they were last selected for an adopted country.

Thomas, who won the last of his seven England caps against New Zealand in 2014, follows players like Jean Kleyn (Ireland to South Africa), Charles Piutau (New Zealand to Tonga) and Byron McGuigan (Scotland in Namibia).

Full-back Leigh Halfpenny, meanwhile, will win his 100th cap as Wales step up their World Cup preparations after tough training camps in Switzerland and Turkey.

Gatland added: “I have been really pleased with the players’ effort and commitment in Turkey, Switzerland and the mini camps in Wales, but now it is about putting what we’ve been training into practice.

“There is some great competition among the squad in all positions, and we’ve selected a team this week with a few debutants because we want to give them the opportunity to see what they can do.

“There is a lot to play for over the next three matches, and everyone is still in contention to make that final squad for France.”

Centre Llewellyn, who is the son of former Wales lock Gareth Llewellyn, will partner George North in midfield, with Cardiff props Domachowski and Assiratti also gaining immediate chances to shine.

Swansea-born Plumtree, meanwhile, goes straight into the matchday 23 after linking up with the Wales squad ahead of last month’s trip to Switzerland.

He has played Super Rugby in New Zealand and will be part of the Scarlets set-up next season.

For Halfpenny, Saturday’s game sees him reach three figures almost 15 years after he made his Wales debut as a teenager against South Africa.

He will become the ninth Wales player to clock up a century, and only the fifth back, joining North, Biggar, Stephen Jones and Gareth Thomas.

Gatland said: “I would like to make a special mention for Leigh Halfpenny, who will win his 100th cap for Wales on Saturday.

“Reaching this milestone is an incredible achievement and testament to the player and person Leigh is. I know it will be a very special day for him and all his family.”