The Waterford man won his heat early this morning and has taken to twitter to express his delight.
Barr says he's smiling from ear to ear and can't wait until Thursdays final.
He's the first Irish man to qualify for a Sprint final at the Olympics since Bob Tisdall in 1932.
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In diving Oliver Dingley finished a very respectable 8th in the 3 metre Springboard final.
The 23 year old was even in medal contention early on.
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Irish golfers Leona Maguire and Stephanie Meadow will finally get their Olympics underway today.
After a long wait in Brazil, the pair will both be in action on the opening day of the Women's Golf tournament.
Maguire will be in the first trio to tee-off this morning at 11:30am – Irish time.
Meadow will get her tournament underway shortly before 1pm.
Meanwhile, Ciara Everard is the only other Irish Olympian in action today.
She competes in Heat 1 of the women's 800 metres, which is due to get underway at 14:55pm, Irish time.
