New York, Sep 4 : A visibly shaken world No. 3 Stefanos Tsitsipas of Greece looked devastated following the five-set loss to Spanish 18-year-old Carlos Alcaraz In a Friday night third-round encounter at the US Open but gave full credit to the world No. 55 for the 6-3, 4-6, 7-6(2), 0-6, 7-6(5) win. "He can be a contender for Grand Slam titles. He has the game to be there." On the last point of the match, Alcaraz slammed an unplayable forehand and fell to the court in celebration. That unplayable forehand -- his 61st winner of the match -- was a reflection of the fearless game the Spaniard played at the Arthur Ashe Stadium on Friday evening. " ball speed was incredible. I've never seen someone hit the ball so hard. [It] took time to adjust. [It] took time to kind of develop my game around his game style," Tsitsipas said. "It's one of these matches and one of these feelings where you pick up [your level] at some point of the match, you feel like you're in control, and it doesn't really go your way at the end," Tsitsipas told atptour.com. "It's kind of bitter, especially after such an incredible fourth set by my side, dominating, being just so aggressive, not dwelling on the past. It was a great fourth set. I felt like he played the fifth one completely the way he played the first set basically, careless, going for every single shot. I have never seen someone play such a good fifth set, honestly." After Tsitsipas fell behind two-sets to-one, he won the fourth set in 27 minutes and it appeared that Alcaraz -- who received treatment on his upper leg before the decider -- would need a big effort to spring the upset. The 18-year-old bounced back like a veteran. "He dealt with it really well. That's something that's going to [help him] reach the top and make him the player that he is. It was supposed to be my match," Tsitsipas said. "Today was a match that I shouldn't have lost. I can only learn from it." "He's young. He fought, he never gave up. I had my opportunities in the third set, lost them," Tsitsipas said. "I feel if I would have won that third set, I don't know if [the] psychology would be the same and the attitude. You saw what happened in the fourth. I was literally flying." Tsitsipas spoke in glowing terms about his opponent ahead of the match, and acknowledged his bright future. But one thing surprised the third seed about the Spaniard: his consistency. "I was returning pretty deep, applying pressure on my returns. I don't know how much harder I needed to hit my return in order to apply pressure," Tsitsipas said. "But he [seemed] to be dealing with it really well, comfortably, hitting winners after the first return of mine, just being so much in control, which was surprising, especially in the fifth set. "I didn't expect him to raise his level so much, especially after having lost the fourth set this way. He was a completely different player." /IANS