Carlos Alcaraz moved into the quarter-finals of the Barcelona Open with a straight-sets defeat of Roberto Bautista Agut, but it was a miserable Thursday for Alexander Zverev on home soil.

Defending champion Alcaraz won an all-Spanish contest with Bautista Agut 6-3 7-5 on Pista Rafa Nadal.

Top seed Alcaraz will face another compatriot in the form of Alejandro Davidovich Fokina, who saw off Emil Ruusuvuori, for a place in the last four in his homeland.

Eyeing a third title of the year, 19-year-old US Open champion Alcaraz was a break down at 3-2 in the opening set before winning six games in a row to take the opener.

Bautista Agut broke the teenager's serve twice midway through the second set, but the favourite reeled off nine points in a row to seal victory in an hour and 54 minutes.

Second seed Stefanos Tsitsipas defeated Denis Shapovalov 6-3 6-2, and Jannik Sinner, the fourth seed, battled past Yoshihito Nishioka 6-1 4-6 6-3, but Casper Ruud was beaten by Francisco Cerundolo in straight sets.

Lorenzo Musetti and Dan Evans advanced at the Real Club de Tenis Barcelona-1899 along with Alex de Minaur, who went through with a walkover as Grigor Dimitrov withdrew due to injury.

Meanwhile, there will be no third BMW Open title for Zverev in Munich this week after he suffered a shock loss at the hands of world number 82 Christopher O'Connell.

Australian O'Connell saw off the third seed 7-6 (7-2) 6-4, while defending champion and top seed Holger Rune ousted Yannick Hanfmann 6-3 6-4, and Taylor Fritz got past Marton Fucsovics in three sets.

Lorenzo Sonego was another seed who bowed out, Cristian Garin beating the Italian 6-3 7-6 (7-3).