That's it for Liam Boyce - he can't carry on so Shay McCartan of Bradford is on.

Liam Boyce just about clears that one away. But the Burton forward is soon down again, he's in the wars.

Head up Dave, we go again. Northern Ireland make a bit of a mess of another set-piece before Joel Campbell hits a shot against the head of Aaron Hughes and away.

Corner ball...

David: Did Costa Rica know they'd organised a friendly against a Northern Ireland Sunday league combined XI? This is awful

Some of the crowd don't like this - Keylor Navas is off, with Leonel Moreira coming on. A strange time to make what looks like a pre-arranged change.

A decent save! Johan Venegas gets in between two Northern Ireland defenders and hits a decent strike from 20 yards but Trevor Carson is well behind it and pats it down.

Looks like Keylor Navas is coming off for Costa Rica...

John O'Neill
Former Northern Ireland defender on BBC Red Button

Costa Rica have been threatening from corners. It was well worked by them but poor defending by Northern Ireland.

How can the Green & White army respond? They win a throw in a good area which allows Josh Magennis to wind up, but his hurl into the box is well defended again.

James: Some of the NI players are in the shop window (Evans, McNair etc) and also we will be in trouble when Hughes, McAuley and maybe Brunt call it a day

A drinks break as we tick past the midway point of the half. It's approaching noon in San Jose. Scorchio!

Liam Boyce goes down in a heap on halfway but thankfully he's soon back on his feet. The ball in from the right is tame though and that's easy for Keylor Navas. Northern Ireland having a decent spell of possession now though.

John O'Neill
Former Northern Ireland defender on BBC Red Button

That was a great piece of play by Northern Ireland but we want to get Stuart Dallas round the outside. If he gets round the full-back it will cause problems for Costa Rica.

This was a great chance for Oscar Duarte...

Good movement from Liam Boyce, who finds space up front and then feeds it out wide to Stuart Dallas. Loads of space for the Leeds man but he comes inside on to his right foot and the ball in is poor.

Image source, Reuters

Gareth McAuley in the right place again to head the ball away. All day long, meat and drink for the big man. Northern Ireland clear the corner too.

John O'Neill
Former Northern Ireland defender on BBC Red Button

Trevor Carson got away with that and I don't know what he was thinking trying to come and get that. The ball was whipped in at great pace and he was never getting there.

Well out! Gareth McAuley reads a cross well and heads the ball clear. The 38-year-old is a relative youngster in the Northern Ireland backline...

Should be 1-0! Trevor Carson comes for the corner, never getting there, and Oscar Duarte heads wide.

Costa Rica's best effort yet. Arsene Wenger may give Joel Campbell a game one day - wherever he ends up...

Keylor Navas appeared to get a minute's applause there for some reason or another. He must be the only Costa Rican to win three Champions Leagues.

Josh Magennis hurls in a long throw which is headed away.