Northern Ireland will look to build on Thursday’s win over Luxembourg when they continue their Nations League campaign away to Bulgaria on Sunday.

Here the PA news agency looks at all the key talking points ahead of the game.

Tougher test

Thursday’s win meant that, for the first time in the short history of the Nations League, Northern Ireland could actually say they were off to a good start in the competition. But a trip to Plovdiv to face Bulgaria represents a much tougher test than Luxembourg at home, and the result against a side who took four points off Ian Baraclough’s Northern Ireland during the 2022 World Cup qualifying campaign will provide a better measure of the progress that has been made. “We have made a lot of progress in the last 10 months but the real test of that will be nights like the one against Bulgaria in a competitive game where we are away against a difficult opponent,” boss Michael O’Neill said.

Captaincy question

Paddy McNair joined O’Neill in Saturday’s press conference, but the manager pointedly refused to say who will captain Northern Ireland in the match. In indicating that he will rotate the captaincy throughout this Nations League campaign before selecting a permanent successor to Jonny Evans ahead of the World Cup qualifiers, O’Neill has made clear he feels the issue of the armband is over analysed. But it does matter to both fans and the players themselves, and the manager can expect to keep hearing the same question throughout this campaign, even if he might not want to answer.

Clean sheets

Northern Ireland have now won four of their last six matches, and all four of those wins have come without conceding. Much has been made of the loss of Evans but the Manchester United defender did not play in any of those four games and Northern Ireland have found a new resiliency without him. Take away the 5-1 defeat to a Spain team that was about to go and win Euro 2024, and Northern Ireland have conceded only once in their last six.

Set pieces

It was notable that both of Northern Ireland’s goals on Thursday came from central defenders in Paddy McNair and Daniel Ballard, and both from set plays – McNair’s following a long throw from Ciaron Brown and Ballard’s from a George Saville free-kick. Once a huge strength of Northern Ireland’s, this is something O’Neill and his team have been working on in a bid to help address the outstanding weakness in this developing team – the lack of a true goal-scorer.

Bulgarian resilience

Northern Ireland suffered defeat on their last visit to Bulgaria – a 2-1 World Cup qualifying loss in March 2021 following on from a 0-0 draw at Windsor Park – but had more of the ball and more efforts at goal in both matches. On Sunday they will come up against a side unbeaten in seven games since manager Ilian Iliev took over, although six of those seven have finished as draws.