It's been a case of revolving doors in New York as Stephen Ward joined up with the Republic of Ireland squad on Saturday night even as Glenn Whelan flew home after learning that his son is suffering from an illness.

The Stoke man anchored the midfield during Ireland's brighter periods of play against Costa Rica on Saturday night, and his absence means Martin O'Neill will again reconfigure his formation ahead of tomorrow night's game against Portugal in Meadowlands.

Ward’s arrival deepens options in the fullback line, with James McClean asked to assume emergency left back duties once Marc Wilson left the field injured in the first half.

Wilson’s hamstring is still troubling him but he is staying on in New York for tomorrow night’s game. O’Neill reckoned that the switches he made contributed to the team’s inability to pressurise 10-man Costa Rica in the second half.

“There were a lot of changes in the side, and I think you have to take these things into consideration.

“The 15-minute spell after half-time I thought wasn’t too good from our viewpoint because we never got close enough to them, and that’s the time when we should really be putting that game to bed.

"We lost our way a little bit, we lost a bit of energy in the middle of the field and there were a lot of changes from the side that played against Italy. "

Learning

O’Neill was sanguine about watching Robbie Keane’s penalty parried by Costa Rican goalkeeper Patrick Pemberton and stressed again that the slow-burning series of friendly games are important for what he can learn rather than for pure results.

“Would have been nice to have gone and won the game having had that 20-minute spell where to be perfectly honest with you, we were well and truly second best but it would have been nice to have gone on and won the game and at least, have got some points.

“At the end of the day, I’m learning things and changes in the side that I’ve made.”

Friday night’s team marked the return of Keane, Ireland’s all-time leading scorer, and a first cap for Shane Duffy, the Derry defender experiencing the first rush of international duty.

Remarkable journey

It has been a remarkable journey for Duffy, who suffered a lacerated liver in an accidental collision while training at Gannon Park four years ago.

He underwent emergency surgery and admitted afterwards that he feared he might die.

So Friday night’s debut was a personal as well as professional triumph and Duffy was glowing afterwards.

Duffy didn't try to disguise the fact that he is enjoying the chance to train under the tutorship of Martin O'Neill and Roy Keane. He was a hardcore Celtic fan growing up in Derry city and also grew up well aware of O'Neill's reputation around Foyleside.

“For him to pick me as a manager, he thinks I’m alright, that’s just an honour for me to be in the squad . . .

"Everything has happened so quick for me, it's still a blur for me really. Playing for Ireland, my country, there's no prouder feeling to be here."

It is thought that Tuesday evening’s game will draw a crowd of 40,000, with the prospect of seeing Cristiano Ronaldo the main attraction.

Whether Portugal risk the Madrid star – particularly given the full-on nature of Ireland's clash with Costa Rica – remains to be seen.