Ken Skupski feels he let his brother down after a fatal double fault denied the Liverpool duo a famous Wimbledon victory.
Ken and Neal benefit from the LTA's NTC Access programme, which is for players ranked 100-200 in singles and 31-100 in doubles, providing cost-free access to courts on all three surfaces, coaching, sparring, trainers, and the LTA's tournament bonus scheme.
Ken, 38, and brother Neal, 31, had a golden opportunity to advance to the last 16 but were unable to edge the decider after experienced Ken double faulted to hand Marcel Granollers and Horacio Zeballos victory.
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Granollers and Zeballos, seeded fourth at SW19, took the first set 6-4 and despite the Skupskis levelling in a pulsating second set tie-break, two errors on serve from Ken at 9-8 down in the third proved costly on Court 14.
And Ken, who toppled Granollers and Zeballos to lift the Acapulco Trophy with Neal in March, said: "It's really disappointing from my perspective to find myself on the losing side.
"I feel like I've let Neil down there, and it's annoying. I think we did enough to give ourselves chances to win.
"It's just a big kick in the teeth the way it ended. I double faulted twice in the last game, which is criminal in doubles.
"It's just frustrating - you play for two and a half, nearly three hours, and it's almost like you've handed the win to them in a really good level match.
"It just wasn't nerves - I didn't feel nervous at all. It's just really tough to take.
"He's a very good returner and I didn't want to give him a cheap chance to win it on his racket, but I paid the biggest penalty by losing the match."
Ken and Neal showed all their fighting spirit as they battled back from a set behind to tee up a decider.
But they didn't have it all their own way in the second, almost scuppering a 4-0 lead when the Spaniard and Argentine rallied back to level at four apiece.
The Skupskis held their nerve to take the match to the wire before the third set ensued into a gruelling, heart-thumping affair.
They looked well place to advance to round three but Ken, who reached the Wimbledon quarter-finals with Neal in 2017, made that crucial error that cost the pair dear.
Neal, who slammed his racket in frustration at one stage during the second set, added: "I'm not disappointed in Ken at all.
"But it's disappointing - it was a good match overall and there's a lot to take from it. We'll take the positives."
Elsewhere on Friday, West Derby's Beth Grey was unable to advance in either the women's or mixed doubles.
Grey, 25, went down 6-4 6-3 with Jonny O'Mara against Nicholas Monroe and Renata Voracova in the mixed format and succumbed in a third set decider alongside Emily Webley-Smith against Tereza Martincova and Marketa Vondrousova in the women's.
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