Connor Gannon and Charlie Barry produced the upset of the tournament so far at the ATP Challenger Dublin on Thursday, defeating top seeds Rithvik Bollipalli and Trey Hilderbrand 6-1, 3-6, 10-9 in a tense doubles quarter-final at Elm Park to reach the semi-finals.​The Irish pair, Gannon ranked 562 and Barry 283 in doubles, overcame a combined ranking deficit of several hundred places against opponents whose pedigree far exceeded their own. Bollipalli, ranked 104 in doubles with a career high of 65 and Hilderbrand, ranked 97 with a career high of 94, had been installed as tournament favourites, but were undone by a fiery Irish performance that grew keener as the match went on.The opening set offered little hint of contest, with Bollipalli and Hilderbrand racing to a 6-1 win. But Gannon and Barry didn’t quit, quickly finding their footing to claim a 6-3 win in the second set to level it, which then set up a nerve-testing super tiebreak. In a format where margins are razor thin, the Irish pair edged it 10-9.The statistics of the match reflect how closely matched the pairs were over the three sets. Both sides converted roughly comparable returns, Barry and Gannon saving enough of the critical moments when they had to. They converted just one of four break points but held firm when it mattered.Unlike their on-court celebration, Gannon was characteristically candid about the moment the result appeared on the scoreboard. “I think the first [set], we were just both looking to see it [a point] on the board.” he said. “Once we did, we kind of let out a chuckle and the crowd gave us a clap and we both said that’s not really the clap we’re looking for.” The pair regrouped, and as Gannon put it, focused on “good energy, making some more first serves, and staying disciplined.”Barry, 25 from Limerick, was similarly measured. “Those third set tiebreakers are going to be close,” he said. “The margins are so small on grass court tennis, especially because of the serves, the courts are quicker, more of an advantage of serving. I just kind of have to play every point one by one.” He was, he admitted, “happy when you’re shaking hands with the winner at the end.”They face Jarno Jans and Niels Visker, ranked 193 and 190 respectively, in Friday’s semi-finals. In singles, Grigor Dimitrov’s run in Dublin has come to an end, with the Bulgarian losing 6-3, 7-6 to Hugo Jacquet in a match that was far closer than the scoreline suggests.Dimitrov won 72 per cent of first serve points to Jacquet’s 78 and converted just one of three break points to Jacquet’s three from six. It was those missed opportunities, rather than any collapse in serving, that proved decisive for the former world number three. Jacquet was simply more clinical when the moments arrived.