London, July 3 -- Boulter had been hoping to continue the British success on Court One as her match followed on from Norrie's.
Hopes were high when the 28-year-old made an eye-catching start to her Wimbledon tournament with a rare victory over a top 10 player, upsetting Spain's Paula Badosa.
Boulter went into that match as the underdog, but faced Sierra - ranked 101st in the world - as the favourite and that change in expectation and pressure may have played a part in this disappointing loss.
She found herself 5-2 down in the first set but drew on the home support to battle back, winning the next three games before coming out on top in a tense tie-break on Wednesday.
But it was deja vu in the second set as Boulter was broken again and t...