Republic of Ireland winger James McClean has apologised for his Twitter outburst following his side's 2-1 away victory over Kazakhstan on Friday.

McClean vented his fury for being an unused substitute in Ireland's opening game of the 2014 World Cup qualifying campaign, claiming that he was "fuming".

"i apologise for my tweet last night, it was stupid, disrespectful and i let my frustration get the better of me which still aint an excuse," he wrote on Twitter.

Ireland will take on Oman in a friendly international in London on Tuesday.