Rising star Angel Di Maria can now add the opening international strike in the rebuilt Lansdowne Road to his list of credits while Keane, on a night when he earned his 100th cap, barely came close to adding to his record haul of 43 for the Republic.
It was still at least an occasion for him to remember, even if the game was ultimately one to forget.
In many respects the football was almost secondary given the number of strands leading into and surrounding the match, the most significant of which related to the health of Ireland manager Giovanni Trapattoni, who initially succumbed to a severe bout of food poisoning earlier this week.
The knock-on effect of that, however, was the 71-year-old Italian today requiring abdominal surgery after aggravating scar tissue from a prior operation.
It left Trapattoni watching the game from his hospital bed, handing over the managerial reins for the game to assistant Marco Tardelli.
The fact all 50,000 seats were not full in hosting such prestigious opposition will likely have raised a few eyebrows within the FAI hierarchy, but these are early days and this was only a friendly.
Then there was Keane's historic moment, becoming only the fourth Ireland player in history to achieve a century of caps.
If the result did not go his way, the 30-year-old Spurs striker will always recall, with 15-month-old son Robbie Jnr in his arms, being given a standing ovation by the 45,200 fans before kick off as they honoured his achievement.
But this game was not all about Ireland, however, as Argentina were looking to pick up the pieces after their hopes and dreams of World Cup glory were shattered just 40 days ago by a harrowing 4-0 defeat to Germany in a quarter final.
That embarrassing loss led to the departure of Diego Maradona as manager while for now, temporary faith has been placed in Sergio Batista, a man who played alongside Maradona in Argentina's 1986 World Cup triumph in Mexico.
Batista's first starting line-up still included eight of the names who figured against Germany, including Lionel Messi. The Barcelona forward had the first chance in this game in the eighth minute of the 59 he played, unleashing a turn of pace after collecting a header from Richard Dunne that had fallen into his path.
After turning inside John O'Shea and then spotting Shay Given off his line, his eventual chip was sadly a little too high.
That would have been a more fitting opening international goal than what the crowd were eventually treated to in the 20th minute.
Gonzalo Higuain was 10 yards behind the last Ireland player when goalkeeper Sergio Romero boomed a long goal kick up field.
That was perfectly legitimate as FIFA laws dictate, although it seemed to be the main bone of contention as the Republic players vented their anger at one of the Danish assistants afterwards.
Higuain touched the ball on for an offside Di Maria to then loft a chip over Given, the ball crossing the line with help from the inside of the left-hand post.
Ireland's protests were perhaps a little lengthy for a friendly, but the goal was allowed to stand, after which they were second best for the remainder of the half to an Argentina side never in top gear.
There was a little more zest and zing from Ireland in a second half punctuated by a plethora of expected substitutions for both sides.
Keane, who had dragged one first-half shot well wide, displayed some magic early in the second that culminated in a cross through the six-yard box with no-one on the end to nod home.
Romero's only save then came in the 71st minute when he hauled down a curling shot from Damien Duff that was directed straight at him.
Given's most notable moment followed soon after when he stopped on the line a rasping effort from Fernando Gago.
There was late pressure from Ireland, with Andy Keogh flicking over the bar a Keith Treacy cross, but the home side lacked the nous to break down a comfortable-looking Argentina outfit.