Marketa Vondrousova further demonstrated her potential by defeating the struggling Brit 7-6(5) 6-4 to secure a significant victory and progress into the third round.
Not much has gone right for Konta since reaching the semi-finals of Wimbledon last summer. She appears bereft of confidence and her once steady baseline game has deserted her.
The 26-year-old, who will tumble down the rankings if she doesn’t put up a strong defence of her Miami Open crown later this month, has much to ponder as she tries to arrest her alarming slide.
Konta made a slow start against her youthful Czech opponent – and she was down a double-break after just three games. It took the No.11 seed time to adapt to the lively conditons, however she still managed to pull level on the scoreboard at 4-4.
The first set was a prolonged affair played in unforgiving heat, and the sky-high temperature undoubtedly contributed to the fluctuating quality.
Konta looked set to complete an impressive comeback when she created three set-points chances on her opponent’s serve in the tenth game, but hesitancy prevented her from making the most of a promising situation.
A fourth set-point came and went for the Brit in the 12th game, and she was left to rue missed chances as a tiebreak was eventually reached. At 5-6 in the shootout, Vondrousova clipped a delightful short-angled forehand winner to prise a 75-minute opener from the grip of her opponent.
The first set had been played a frenetic pace, and there was a noticeable drop in intensity at the beginning of the next. Konta made the first move and established a break in the fifth game, but it was a lead she could not maintain.
When the Brit stepped up the line at 4-5, there was a sense of inevitability regarding what would happen next. The Czech was soon in celebration mode after Konta floated a rare backhand slice beyond the baseline.
It was another close battle that had gone against the Brit, but credit must go to Vondrousova, a teenager with a very bright future.
Elsewhere on the grounds, Simona Halep did enough to see off Kristyna Pliskova 6-4 6-4, Petra Kvitova pipped Yulia Putintseva 6-7(4) 7-6(3) 6-4 in a marathon duel and Naomi Osaka netted another big win, this time over Agnieszka Radwanska 6-3 6-2.