Thanasis Kokkinakis switches focus to

An ailing Thanasi Kokkinakis has vowed to throw all his energy into a Wimbledon double act with retiring champion Lleyton Hewitt.

The 19-year-old Kokkinakis succumbed to his illness, and the London heat, in slumping to a first-round defeat in his maiden Wimbledon assault on Monday, but still has an exciting doubles opportunity with Hewitt to look forward to.

Greek Australia teenage sensation, who was laid low with a stomach bug in the past week, admitted to throwing up in his mouth on occasions during his 7-6 (9-7) 7-6 (7-3) 6-4 defeat to 24th seed Leonardo Mayer.

The match nearly dragged into a fourth hour and Kokkinakis lamented a lack of energy and confidence in the loss, but insisted he'd be ready to pull out all the stops to extend Hewitt's Wimbledon goodbyes after the veteran's singles career at the tournament ended with a trademark five-set marathon against Finn Jarkko Nieminen.

"I will treat it seriously as I can," Kokkinakis said.

"I was pretty pissed off when I walked off the court.

"I think because it's Wimbledon and Lleyton's last, I will definitely be into it and give it a good crack."

Despite reaching the third round at the French Open a month ago, Kokkinakis endured an awful preparation for the grasscourt tournament, with the death of his grandmother hitting the 19-year-old hard before he was struck down by a serious intestinal infection.

"I'd be lying if I said my preparation was ideal," said the world No.69.

"Last two weeks after French I actually had a really good week training on the grass, and then couple of things happened.

"As soon as I came back home and started to train well again, I got sick. I don't know what it was.

"I'm still finding out what antibiotics I'm about to take now."

Kokkinakis looked the better of the two in the first set, but Mayer's experience shone through in both tiebreakers.

Kokkinakis  drew on heavy crowd support to save two set points but crucially put a straightforward volley into the net to throw the set away.

"I managed to get it to two tiebreakers, had a good chance in the first set," he said.

"I had a good chance to break early in the second, as well. Didn't take it.

"(Then) got up a break in the third and got broken straight back."

Kokkinakis is no stranger to five-setters, having come from two sets down to defeat compatriot Bernard Tomic in Paris last month.

He again displayed those same fighting qualities, saving two match points before luck went against him.

Serving to stay in the match, the youngster looked on in despair as a firm Mayer backhand clipped the net and dropped harmlessly to close out the three-set win.