Bernard Tomic dug deep to overcome a mid-match dizzy spell, and losing a two-set lead, in an upset win over American 21st seed Sam Querrey at Wimbledon on Tuesday.

Tomic called a doctor in the fourth set of a 7-6 (8-6) 7-6 (7-3) 3-6 2-6 6-3 victory complaining of dizziness and poor vision, later attributing the problem to under-eating at breakfast.

The world No.59 joined Samantha Stosur and Lleyton Hewitt in the second round, but James Duckworth and Matt Ebden lost their first-round matches.

Tomic next faces American veteran James Blake in the second round on Wednesday and he was relieved to have survived Tuesday’s gruelling encounter against big-serving Querrey, who blasted 36 aces.

“I felt very bad out there,” Tomic said.

“I lost my energy and I think that was due to I didn’t eat as much in the morning.

“Lucky, somehow I won. Nightmare.”

Trailing Querrey 4-1 in the fourth set, Tomic received treatment for around 10 minutes.

Querrey was reportedly angered, feeling Tomic should have played through the problem, but Tomic defended the move.

“He has to put himself in my shoes if he was feeling bad,” Tomic said.

“At that time I was doing the best thing to make myself feel as good as I can on the court.”

Tomic’s win helped put him put behind a troubled few months featuring injury worries and the drama surrounding his father and coach.

“It’s big. To win here, to beat a big seed like Sam, is a good feeling,” Tomic said.

John Tomic, who is facing an assault charge, was not on-site, with his ATP coaching credentials suspended and Wimbledon officials barring him from attending, even as a spectator.

Bernard Tomic took another opportunity to blast ATP officials over the matter and said he would lobby tournament official in the hope his father could join him for the rest of the tournament.

After the Australian won two tight sets, the momentum swung Querrey’s way in the third and Tomic’s declining health allowed him to quickly square up the match.

Tomic admitted “not trying as much” in a bid to save his energy but said he never considered giving up.

The tactic paid off as Tomic lifted again in the last set, securing the crucial break at 4-3 up with a succession of brilliant winners and then serving out the match.

Earlier, Stosur blasted her way into the second round with a dominant 6-1 6-3 win over Slovakian teenager Anna Schmiedlova.

The 14th seed declared it one of her better performances on grass as she set up a second-round clash with Russian Olga Puchkova.

“I feel pretty good going into the next round,” Stosur said.

A strong fightback proved in vain for Duckworth in a 6-4 6-2 3-6 4-6 6-1 loss to a fellow qualifier, American Denis Kudla.

Wild card Ebden became the fourth Australian man to lose in the first round when he fell in a 6-2 6-4 6-3 defeat to Japanese 12th seed Kei Nishikori.

Hewitt upset Swiss 11th seed Stanislas Wawrinka on Monday to set up a second round match against German Dustin Brown on Tuesday, while Marinko Matosevic and Matt Reid were first-round losers.