John O'Shea conceded that Ireland's inability to make their possession count left them open to the rapier-like counter-attacks that gave Belgium a 3-0 victory at Euro 2016.
A defensively-minded Ireland managed to restrict Belgium's attacking threat in getting to half-time 0-0, but attempts to press forward after the interval were ruthlessly punished by Romelu Lukaku (twice) and Axel Witsel.
"The big thing for us was to make sure that we started the second half that bit quicker and that bit better in possession," O'Shea told RTÉ Sport.
"But we didn't do that, we left ourselves too open to that counter-attack."
It was a vastly different performance from Ireland's opening game against Sweden, when Martin O'Neill's side looked composed on the ball and controlled long spells of the game.
O'Shea added: "In patches, the first half was OK, but not good enough in terms of how we played against Sweden, how good we were on the ball and that clinical edge in terms of keeping our shape and keeping our compactness, especially when we were attacking, that's something we're going to have to improve on.
"It's not just a case of keeping 10 men behind the ball, we did that at times, but when you're attacking, it's that cliché that you're sometimes at your most vulnerable."
Ireland now face Italy on Wednesday knowing victory is a must if they are to qualify for the knockout stages, but despite today's disappointment, skipper O'Shea believes his side have shown enough to be confident of getting a result.
"Belgium are a good team, don't get me wrong but we have a big chance now against Italy," he said. "We know it'll be difficult, Italy have been fantastic in their first two games.
"But we have to take the positives from the first half tonight and the game against Sweden, and if we do that, with a bit more discipline and control, I think we can get something from Italy."
John O'Shea gave an honest assessment's of Ireland's performance and wants the focus to turn to Lille. https://t.co/eookdFoMZZ— RTÉ Soccer (@RTEsoccer) June 18, 2016