PARIS, Nov 5 (Reuters) - Novak Djokovic stayed on course for a sixth Paris Masters title with 6-4 6-3 win over American Taylor Fritz while world number two Daniil Medvedev tamed home crowd favourite Hugo Gaston 7-6(7) 6-4 to reach the semi-finals on Friday. Alexander Zverev made sure three of the world"s top four will compete in the last four after he toppled Casper Ruud 7-5 6-4 while Poland"s Hubert Hurkacz dug deep to beat Australian James Duckworth 6-2 6-7(4) 7-5. On Saturday Djokovic will meet Hurkacz while Medvedev will lock horns with Zverev in a mouth-watering clash for berths in Sunday"s final. Djokovic and Fritz traded fierce ground strokes in the first set before the 20-times major winner broke serve at 3-4. Fritz broke back immediately but Djokovic"s supremacy from the back of the court finally told as he clinched the opener in 38 minutes. "I was absent from the Tour for two months, coming into this tournament, and the last competitive match I played was in the U.S. Open final, compared to the other guys playing one or two events prior to Paris," said Djokovic, who lost to Medvedev in the final at Flushing Meadows. "I knew that I needed to start well, with good intensity and put in a lot of hours on the practice court. But it"s different when you play points in a competitive match." The pair again exchanged service breaks at the start of the second before Fritz blew a chance at 1-1 with Djokovic down 15-40. The Serb seized control after overcoming that minor blip, winning 12 of 14 points from 2-2 to register his fifth straight win over the 24-year-old American. "I did have ups and downs. I am not really pleased with the way I closed out the sets. I lost my serve to love (at 1-1), then (at) 5-3, again, I served for it with new balls and lost to love again. Those things shouldn"t happen," added Djokovic. Medvedev double-faulted to hand Gaston a 5-4 lead in a knife-edged opening set and then saved three successive set points on the Frenchman"s serve to force a tiebreak as the next two games went with serve. More spectacular shots and nerve-jangling action followed as Gaston saved a set point with a delicious backhand winner before Medvedev eventually clinched the hour-long set with a service winner which silenced vocal home fans in Paris. The Russian raced into a 4-0 lead in the second set but 21-year old Gaston, who rallied from a 5-0 second-set deficit to beat Spaniard Carlos Alcaraz in the previous round, won the next three games and got the crowd back on their feet. Medvedev held his nerve though and sealed the pulsating contest with a forehand crosscourt winner in a jittery final game in which he double-faulted on his first match point. Zverev was in cruise control against Ruud after breaking the Norwegian"s serve in the 11th game of the opening set, holding his own throughout to book his last-four berth.