Local hero Kokkinakis compared the balls to "lemons" after his dream of replicating his thrilling, emotional ride to the 2022 at Memorial Drive as a wildcard were quashed on Monday night by party-crashing Lajovic, 3-6 6-1 6-4.
Kokkinakis felt the balls used neutralised his powerful serve and were the softest he had encountered outside last year's Cincinnati Masters.
"I remember here usually being a lot quicker," he said.
"(Serving only) four aces is not something I'm used to, especially on a fairly quick playing surface.
"When the balls get super slow it feels like there's a ton of time on return.
"They're a lot slower than (anywhere) last year in general for the most part, maybe barring Cincinnati.
"He (Lajovic) was rolling them on his sweat to try to speed them up a bit.
"The balls, after a few rallies, get super slow and they turn into lemons.
"It makes it tough, especially when it's colder, to get much power on the ball."
While clearly frustrated by the balls, Kokkinakis felt the match was lost on his own racquet, notably during the match-turning second set.
After storming ahead 6-3, Kokkinakis lost his way, conceding 26 of 37 points in the second-set rout
"I don't think it was him playing incredible in that second set," he said.
"He was steady, he's a good pro and a tough player.
"It looks like a 6-1 set but it was just me losing focus.
"I felt like a lot of it was on my racquet - I made a few errors and all of a sudden it's a dogfight."
Kokkinakis, searching for his maiden win of 2024 after suffering an opening-round loss to countryman Rinky Hijikata in his return in Brisbane last week, knows he needs to be better at pressing home any early advantage.
"It's been a trend in a lot of my matches, early in the second set my feet stop and I lose my focus," he said.
"That's my biggest weakness to be honest.
"When I'm playing well I take my foot off the gas.
"I maybe go for some shots that aren't there and lose a bit of focus.
"It changed the whole momentum of the match."
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