Hidalgo-Clyne put in a man-of-the-match performance and kicked 13 of his side's points as he continued his recent stellar form for club and country.
WP Nel and Fraser McKenzie crossed the whitewash for the visitors before the TMO ruled that Exiles hooker David Paice was held up over the line as the clock went red to seal the deal.
Alan Solomons' troops face a GUINNESS PRO12 clash with third-placed Munster before the Dragons game and Hidalgo-Clyne believes the defensive resilience they showed against Irish bodes well for the future.
"They really put us under pressure at the end but it was fantastic the way the boys dug in and we kept our defensive structure," explained the scrum-half.
"Towards the end of the first half we were hanging on a bit and they were putting a lot of pressure on us.
"They stretched our defence really well and we knew that we would continue to be tested in the second half but the boys stuck to it.
"It's absolutely massive to make the semi-finals, it's fantastic for Edinburgh Rugby and it's brilliant that we've got a home fixture at BT Murrayfield against the Dragons - we're looking forward to it.".
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