Steve Howard scored on his Scotland B debut to salvage an undeserved draw as the Irish did more to suggest that they have international strength in depth.
Chris Iwelumo and Steve Howard both made their Scotland B debuts
Scotland goalkeeper Graeme Smith performed heroics to deny Noel Hunt and Richie Byrne either side of the break.
But, after Smith had done superbly to turn a Mark Yeates drive against the crossbar, Byrne turned the ball home.
The Scots equalised late on when substitute keeper Dan Connor was deceived by a Howard header.
Both countries had used the fixture to give players their first taste of international football.
And, for the home side, it was a chance to confirm English-born duo Chris Armstrong and Howard as Scottish property.
Alex McLeish's second string looked to have received inspiration from the senior side's much-lauded narrow defeat by Italy on Saturday as they dominated the early exchanges.
Michael Stewart sent a good chance wide, but the Irish gradually took control as the game fell flat in front of 3,133 fans at Airdrie's Excelsior Stadium.
Hunt had already fired powerfully at Smith from long range by the time the Scotland goalkeeper was forced to pull off a superb stop following a comical mix-up in the home midfield.
Stewart kicked Kevin Thomson as both went to take a quick free-kick, the ball broke to Hunt and he unleashed a powerful effort from the edge of the box that Smith did well to thwart at full stretch.
Hunt was clattered moments later by Darren Dods, who probably will not be thanked by his Tannadice team-mate or their club manager, Craig Levein.
Scotland were relying too heavily on long balls looking for Howard and another debutant, Chris Iwelumo, who were proving to be a rather static pairing up front.
Ross Wallace did force Irish goalkeeper Colin Doyle to touch a 20-yard rocket over the crossbar just before the break.
Richie Byrne (right) put the Irish ahead at Excelsior Stadium
But the Republic's grip on the game tightened further in the second half.
Smith came to the rescue again to brilliantly push clear Byrne's diving header and Roy O'Donovan sent his effort on the rebound wide via a deflection.
But the Irish deservedly went ahead after 65 minutes, when Aberdeen defender Byrne was on hand to pounce after Smith had denied impressive substitute Yeates.
The Colchester United striker was unfortunate not to win a penalty minutes later following a Charlie Adam challenge and then sent another effort just wide.
Drogheda United keeper Connor had only just replaced Doyle in the Irish goal when he was beaten in the 83rd minute.
Howard was unable to put much power into his header from an Armstrong cross, but the ball came off the post, bounced back into the field of play then spun over the goalline.
As the revitalised Scots pressed for a winner inspired by the introduction of strikers Ross McCormack and Steven Fletcher, Republic defender Jim Goodwin was sent off for a second yellow card, but the visitors held out for the draw.
Scotland B: Smith, McNaughton, Armstrong, Berra, Dods (Collins 46), Stewart (Broadfoot 72), Whittaker (McCormack 68), Thomson (Adam 46), Iwelumo (Fletcher 60), Howard, Wallace.
Subs Not Used: Samson.
Booked: Wallace, Armstrong.
Goal: Howard 83.
Rep of Ireland B: Colin Doyle (Connor 81), Goodwin, Dillon, Bruce, Gartland (Bennett 80), Whelan (Byrne 30), Walters (Bell 62), Michael Doyle, Hunt (Yeates 53), O'Donovan (Ward 53), Hoolahan.
Sent Off: Goodwin (89). Booked: Goodwin.
Goal: Byrne 65.
Ref: Joseph Attard (Malta).