O'Neill: We're badly missing Robbie's killer instinct in goalmouth
The Irish boss was frustrated by opportunities squandered in Sunday's loss to Turkey which followed on from errors in front of goal in the March reverse to Serbia, with Shane Long admitting his frustration at missing chances.
Keane, Ireland's record goalscorer, is only taking part in the US leg of the summer schedule and O'Neill conceded that the Turkish match illustrated his importance.
"I would have to agree with that," said the Derry man. "I suppose there's a feeling, and it never works out that way, but you get a feeling Robbie might have put one of those chances away.
"Still, putting the ball in the net is difficult. Maybe it's not as hard as we make it out to be but our return – for the number of really decent chances we've created in the two games – should be a lot, lot better."
The 62-year-old was more cautious when discussing the importance of getting Dunne back into the fold after his heroics for QPR in Saturday's play-off triumph over Derby County. He signed himself out of the summer internationals due to the effects of a long season and O'Neill learned of that decision through the media rather than speaking with Dunne.
"I've spoken to him some months ago but before I got back to speaking to him again, he'd said he'd ruled himself out of these games but not ruled himself out of playing for Ireland again, so I'll assess it closer to the time," said O'Neill.
O'Neill also offered his sympathy to Richard Keogh after his play-off nightmare at Wembley and won't rush him into preparations for Saturday's friendly with Italy. The 27-year-old Derby defender was due to link up with the Irish squad last night along with Jeff Hendrick and Conor Sammon but O'Neill will be understanding of their situation.
Both Keogh and Hendrick played a full part in a cruel defeat, while Sammon was an unused member of the squad.
"You're talking about energy-sapping stuff," said O'Neill. "It'll have killed them and it's getting over that maybe that will be the big thing."
Young 'keeper Ian Lawlor has joined the squad in different spirits. The Manchester City teenager has been given a bonus call-up to train with the first-team squad this week and provide cover for the Italy match as Rob Elliot is missing due to his wedding. However, 32-year-old Coventry stopper Joe Murphy would play if David Forde sustained a knock.