The Charlton midfielder struck after only five minutes when he hooked home Steve Finnan’s right wing cross from six yards.

But the USA - five places above the Republic in the FIFA world rankings at 13 - hit back after 34 minutes when Eddie Pope slipped past Rory Delap and headed home John O’Brien’s left-wing corner.

Heavy rain all day in Dublin left the pitch in an awful state and the conditions for flowing football were at times nothing short of farcical.

When the match got under way, the Republic had little option than to try and build down their right flank, as the nearside of the pitch in front of the dugouts was so wet that the ball got stuck in the puddles and made any attempt to play football a farce.

The Americans had unwittingly conned McCarthy with the line-up which was announced before the game, as their team played according to squad numbers rather than one to 11, so Everton’s Moore was in fact on the bench.

But the Republic got their own back as they made a dream start by scoring after only five minutes.

Fulham skipper Steve Finnan made a surging run down the right and delivered a teasing cross into the six-yard box where Charlton’s Mark Kinsella hooked home a volley for his third international goal.

That took the Republic’s tally under McCarthy to 98 goals, leaving them plenty of time in which to try and notch up the ton tonight.

Football may not be one of the main sports in America, but their team are no mugs, and in their last two friendlies they lost narrowly to Italy and Germany.

A glimpse of their talent came after eight minutes when Clint Mathis let fly from 25 yards and Shay Given produced a wonderful flying save to tip the ball over his bar.

It was hard to believe that had this not been a sell-out, and live on television, the match would have gone ahead, as the conditions made for scrappy football and clumsy tackles.

The Republic won a free-kick on their left after 19 minutes thanks to one such clumsy challenge by Tony Sanneh on Damien Duff, but Ian Harte’s cross was too deep for any team-mate to connect with.

Kinsella came within inches of scoring a second goal after 25 minutes.

Robbie Keane did well down the left and sent a cross into the six-yard box. Kinsella dived full length to try and head it home, but just failed to reach the ball and Jeff Agoos made the clearance.

The Republic were determined to keep their proud run going. They have lost just once in their last 19 matches, and are unbeaten in the last 10 on home soil, although McCarthy would have been more concerned with performances as he looks to finalise his squad for Korea and Japan.

There was an exciting moment after 31 minutes when Keane’s through-ball almost let in Duff on the edge of the box, but Friedel was out swiftly to deny his Blackburn colleague and clear with his legs.

The USA enjoyed a spell of pressure soon after when they forced successive corners, and from the second one they grabbed a 34th-minute equaliser.

John O’Brien curled in a cross from their left and Eddie Pope slipped past Delap to beat Given with a downward header into the far corner.

Given had to react smartly after 38 minutes by diving at the feet of Earnie Stewart following a scramble in the box.

Two minutes later the Irish won a free-kick on their left, but Harte’s deep cross was too close to Friedel, who made a clean catch.

Duff won a free-kick in a better position after 41 minutes when he was tripped by Gregg Berhalter on the left edge of the box. Harte drilled it in low this time, but Kevin Kilbane was unable to control it.

Reyna tried to get things going again for the visitors, and there were a few unwelcome jeers from the crowd aimed at the former Rangers player.

As the half was brought to an end, the Irish knew they had been given a good test, and it remained to be seen how many changes the manager would make at the break.