Martin O'Neill has admitted his only disappointment at working with Robbie Keane was that he did not inherit him until he was 33-years-old.

The Republic of Ireland boss will hand the now 36-year-old striker an emotional farewell as he brings down the curtain on his international career in Wednesday night's friendly against Oman in Dublin.

Keane will win his 146th cap as he attempts to add to his record tally of 67 goals for his country at the Aviva Stadium on a night which will single the end of an era.

The LA Galaxy frontman has played a greater role off the pitch than on it in recent years but he will pull on the green shirt for the final time having written himself into the nation's sporting folklore.

O'Neill said: "Since I've come, the only disappointment I would have had is that I didn't have a 27-year-old Robbie Keane rather than a 33-year-old, at the time, I think he was.

"He's been a terrific, an absolutely terrific player and certainly he will be hard to replace.

"Robbie will take away some great memories with the number of games he has played, the number of goals he has scored.

"He still showed even though he didn't start in some of the games and you would talk about him being a proper captain."

The Ireland manager sees a future for Keane in the game and believes it would be a waste if he were to walk away from football.

"The most important thing is that he stays in the game in some capacity," O'Neill insisted. 

"We were chatting the other evening and I said just stay in the game. Once you retire at club level if you're not in you will miss it.

"He's doing his badges and everything possible. I don't see why not. There's no reason why lads who have management in mind should not go and further it."

For all the talk over Keane's final game, the clash with Oman game is a low-key one. The visitors have drawn with League of Ireland sides Cork and Limerick during their tour of the country - it will also serve as a warm-up for Monday's opening World Cup qualifier in Serbia.

As a result, O'Neill knows he will have to strike a balance between the sentiment of Keane's final bow and the business of honing his squad for the onset of hostilities.

He said: "I haven't told him whether he will start the game, but he will certainly be participating in the game. There's a fairly decent chance he will start the game."

He added with a smile: "Is he one [goal] behind Gerd Muller? Is he? Well, he'd better do it in the first 20 minutes of the game because he's going to find time pressing, really pressing."

Neither Seamus Coleman nor James McCarthy will feature against the Omanis as they continue their recovery from ankle and groin injuries respectively, while defender John O'Shea will join up on Wednesday after staying at club Sunderland for treatment on a hip injury.

O'Neill revealed he had urged 35-year-old O'Shea not to follow Keane and Shay Given into international retirement after Euro 2016.

He said: "I still believe that John has something to offer for us in every capacity, so I just thought if he was thinking about retiring at that stage maybe just to have second thoughts.

"On the strength of that, then John thought, 'Well okay, let's see how it goes from here and take it on'."