Madrid, Apr 19 (Reporter) Top seed Carlos Alcaraz went through to the Barcelona Open semi-finals with a straight-set win over Alex de Minaur. Spaniard Alcaraz needed just one hour and 40 minutes to beat Australian fifth seed De Minaur 7-5 6-3. The world number two will now play France's Arthur Fils after his quarter-final opponent Stefanos Tsitipas retired hurt in just the third game of their match. Alcaraz beat 20-year-old world number 14 Fils in three sets on his way to winning in Monte Carlo last week, the BBC reported. Defending champion Casper Ruud went out thanks to a straight-set defeat by Denmark's Holger Rune. Alcaraz twice fell a break down in the first set against De Minaur before recovering and making the decisive break in the 12th game. The 21-year-old was more dominant with his serve in the second set and made the only break in the sixth game. "I started quite badly with the serve, I was struggling a little bit mentally with it," said Alcaraz. "It was just the first few games with my serve, then I think I improved a lot. I calmed myself down and started to think positively again. Alex started strong, playing aggressively, and the first set was really tight. "I'm really glad I managed to win the first set and in the second I played some great tennis, so really happy." Four-time runner-up Tsitipas looked uncomfortable from the off against Fils and left for an off-court assessment at the end of the second game. He returned but could only manage five more points and retired while 0-2 30-40 down. World number 13 Rune broke defending champion and second seed Ruud twice in each set to secure a 6-4 6-2 win. Sixth seed Rune will play Karen Khachanov in the semi-finals after the Russian beat Spain's Alejandro Davidovich Fokina 6-4 7-5...////...