The error helped Konta grab the break but Garcia soon found her range and by the end of the set it was the Frenchwoman cranking up the pressure.
There was a slight blip when serving for the set at 5-1 as Azarenka earned a break back, but it only delayed what had always been an inevitable Halep win as once again the former world number one contrived to cough up cheap points on serve and, with it, the match. Again she showed why she has as good a chance as anyone of winning the whole thing on Saturday.
There was very little between the two players as Garcia, ranked No21 in the world, matched Konta's impressive power in rallies and on serve throughout.
Garcia's father, Louis Paul, is also her coach.
So it went to a tie-break but Konta, to her credit, did not allow her frustration to deter her. The home favourite raced into a 3-0 lead, then hit a brilliant forehand victor with Garcia at the net. Early in the second set she broke Konta, who was struggling to find the same range with her forehands as she did at the start.
Her level dipped in the second as French star Garcia's rose, and at 5-1 it looked a foregone conclusion.
"It's very exciting", Konta said in her postmatch press conference.
World No. 2 Simona Halep of Romania and No. 6 Johanna Konta of Great Britain were victorious in the Round of 16 at Wimbledon on Monday and will face off against each other in the quarterfinals at the All England Club.
Garcia should have closed the gap to one but her drive volley was met with a sizzling forehand pass and instead Konta served out the set with an ace. Even at 5-4 there had not been a break point or even a deuce but then in the 10th game, with Garcia serving to make it 5-5, Konta was just too strong.