Rhys Ruddock's potentially World Cup-ruining injury removed what little gloss there was for Ireland in a "frustrating" win in the Tbilisi Cup.
The South Americans were relentlessly stubborn; they competed well at the breakdown and claimed a well-earned a penalty try in the second half.
By the time Ireland lost skipper Ruddock after 20 minutes, they were already 19-0 ahead following tries from Eoin Griffin, the outstanding John Cooney and Cian Kelleher.
Munster tighthead Stephen Archer already had his opposite number under real pressure, and when Uruguay's pack were cut to seven forwards by a yellow card, Ireland's scrum won a penalty try on the stroke of half-time.
But Kelleher was binned for cynically blocking a pass as Los Teros made life distinctly difficult for Ireland in the second half.
Loosehead James Cronin struggled in the sweltering 35-degree heat.
Archer's surge followed by Rory Scannell's delayed pass handed Griffin an easy finish for the opening try inside five minutes.
Billy Holland and Reid were stopped short but scrum-half Cooney picked up and dived over for the second before good passing handed Kelleher a simple finish.
Ireland looked to be strolling to a comfortable win before mistakes fuelled a gutsy Uruguay response.
"At times in the first half we looked a very good team but in the second we were distinctly average," admitted Clarke. "We made mistakes which gave Uruguay energy. The boys are frustrated and we have plenty to work on."
Emerging Ireland - P Nelson; C Kelleher, E Griffin (L McGrath 66), N Reid (JJ Hanrahan 68), A Conway; R Scannell, J Cooney; J Cronin (D Buckley 59), D Heffernan (R Herring 59), S Archer (A Warrick 50), A Browne, B Holland (B Marshall 50); R Ruddock (capt, D Leavy 20), E Masterson (J Conan 59), F Taggart