The Manchester United midfielder, elevated to the role of captain this season by his club following the depature of Eric Cantona, almost single- handedly hauled the Irish back into the World Cup reckoning here just when it looked as if their quest to qualify for their third consecutive finals was doomed.
Slipshod defending either side of half-time found a stunned Irish side suddenly trailing 2-1 when Keane took a hand. In the space of 10 minutes he trebled his goal output for his country, keeping his head while all around others were losing theirs (not always one of his strengths), to put the Irish back in control of their destiny.
Mick McCarthy, Ireland's manager, believes that there is time enough for Keane to take over the captaincy but whether or not he is ready to dispense with the services of the 34-year-old Townsend just yet remains to be seen. It looks, though, as if he will have to loan Keane the armband for the all-important game against Lithuania in Vilnius on Wednesday as Townsend, along with Mark Kennedy and Jeff Kenna, is suspended. Like Iceland's first recorded inhabitants - a group of ascetic Christian Irish monks - the Irish, it seems, have a habit of making life difficult for themselves.
"One or two of the lads know it's the end of an era for them and I've spoken to Andy long and deep about that," said McCarthy. "He's been the centre of some criticism and I would love him to go out with everyone remembering what an absolutely brilliant player he's been for us for 10 years. He's probably suffered by having too many good games."
If Keane's unexpected goal rush was timely, the contribution of Kennedy could not have come a moment too soon. Yet the Liverpool midfielder had been deemed surplus to requirements at the outset, McCarthy opting to award a debut to Kevin Kilbane, of West Bromwich, instead.
By half-time, McCarthy had thought better of it, introducing the young Dubliner, who wasted no time in redressing the error. He made both Keane's goals and set up the fourth, when the home goalkeeper fumbled his cross- shot into the net, before he disappeared again from view, sent off in the 84th minute for a second bookable offence. "He turned the game for us with his ability," conceded McCarthy, even if he did blight his short appearance with "sloppiness and indiscipline."
At 26 Keane seems finally to be curbing his own indiscipline. The Irish could do without any repetition of the last time he wore the armband: it was McCarthy's first match in charge, 18 months ago - and Keane was sent off.
Goals: Connolly (13) 1-0; Gunnarsson (43) 1-1; H Sigurdsson (47) 1-2; Keane (54) 2-2; Keane (64) 2-3; Finnbogason (og 78) 2-4.
ICELAND (4-4-2): Finnbogason (KR Reykjavik); L Sigurdsson (Stoke City), Bergsson (Bolton Wanderers), Sverrisson (Hertha Berlin), Hreidarsson (Crystal Palace); Kristinsson (Lillestrom), Jonsson (Orebro), T Gudjonsson (Genk), Gunnarsson (KR Reykjavik); H Sigurdsson (Stabaek), Danielsson (KR Reykjavik). Substitutes: B Gudjonsson (Newcastle Utd) for Gunnarsson, 63; Gudmundsson (IBV) for Danielsson, 69; Dadason (KR Reykjavik) for H Sigurdsson, 66.
REPUBLIC OF IRELAND (4-3-3): Given (Newcastle Utd); Kenna (Blackburn Rovers), Cunningham (Wimbledon), Harte (Leeds United), Staunton (Aston Villa); McLoughlin (Portsmouth), Keane (Manchester United), Townsend (Middlesbrough); Kelly (Leeds United), Connolly (Feyenoord), Kilbane (West Bromwich Albion). Substitutes: Kennedy (Liverpool) for Kilbane, h-t; McAteer (Liverpool) for Cunningham, 87.
Referee: A Kulusic (Croatia). Sendings-off: Iceland: L Sigurdsson. Ireland: Kennedy. Bookings: Iceland: Sverrison. Ireland: Townsend, Kenna.
Man of the match: Kennedy. Attendance: 5,000.