World number one Novak Djokovic reached the final of the Madrid Open after seeing off last year's runner-up Dominic Thiem 7-6(2) 7-6(4) in a gruelling, high-quality encounter on Saturday that lasted two hours and 22 minutes. The Serbian will meet either five-time Madrid champion Rafael Nadal, the world number two, or Stefanos Tsitsipas in Sunday's final after producing his best tennis since winning the Australian Open in January. Djokovic, winner in Madrid in 2011 and 2016, was fully rested after his quarter-final opponent Marin Cilic had withdrawn because of food poisoning, while Thiem had to dig deep to beat Roger Federer in a gruelling three-setter. Thiem, who had won the Barcelona Open last month and was on an eight-match winning streak, struck an early blow by breaking Djokovic in the fourth game but the Serbian responded by winning the next three games and saved two break points in the eighth. The Serbian won the first tiebreak comfortably after some poor shot selections from Thiem but was in trouble in the second set when he trailed 4-2. He immediately broke back and had the chance to serve for the match at 6-5 but squandered the opportunity with a double fault. Yet once again Djokovic had the edge in the tiebreak, earning three match points and taking the first one as Thiem smashed a baseline backhand well out, booking his place in a first final since winning the Australian Open.