Italian Open: Johanna Konta loses to Jelena Ostapenko in Rome
British number one Johanna Konta was knocked out of the Italian Open on her 27th birthday by French Open champion Jelena Ostapenko.
Latvian fifth seed Ostapenko, 20, recovered from losing the first set to win the last-16 match 2-6 6-3 6-4 in Rome.
Defeat was world number 22 Konta's fifth in a succession against a top-10 player.
Ostapenko will play Maria Sharapova in the quarter-finals.
Konta raced away with the opening set, breaking Ostapenko's serve twice to lead 4-1 after only 17 minutes, then serving out.
She had blown a first-set lead in her three previous matches against top-10 players, and the same pattern followed against the world number six.
Ostapenko soon rediscovered the form which helped her claim a shock victory as an unseeded teenager at Roland Garros last year, landing some ferocious winners as Konta rarely failed to attack her serve in the second set.
Ostapenko broke Konta's serve early in a more evenly contested final set and, after Konta wasted a break point at 3-4 with a wild return, clinched victory in two hours 13 minutes with her first match point.
Romanian world number one Simona Halep was given a walkover into the quarter-finals as American Madison Keys withdrew because of a rib injury.
Reigning champion Elina Svitolina, from Ukraine, beat Russia's Daria Kasatkina 0-6 6-3 6-2.
She will play two-time Grand Slam winner Angelique Kerber in the last eight after the German won 6-1 6-1 against Greece's Maria Sakkari.
France's Caroline Garcia set up a quarter-final with Halep was by beating American Sloane Stephens 6-1 7-6 while Maria Sharapova of Russia also made it through to the last eight with a win over Australia's Daria Gavrilova 6-3 6-4.
The Italian Open is one of the final clay-court tournaments before the French Open starts on 27 May in Paris.
BBC tennis correspondent Russell Fuller
Konta is, to some extent, still in recovery mode - but her prospects look brighter, even though she is still looking for a first win over a top-10 player since last year's Wimbledon.
In the first set, Konta was accurate, aggressive and played with great clarity. There could perhaps have been an opening for her early in the second set, but Ostapenko held on and began to hit her stride.
Konta fought hard in the decider, having dropped the opening game on serve, but her one fleeting chance to break back was missed and she will head to the French Open after a long weekend at home.