Djokovic will play defending champion Roger Federer or third seed Andy Murray in Monday’s final after coming from a set and a break down to topple the 6ft 6in former US Open champion in a gruelling semi-final clash lasting two hours and 11 minutes at London’s O2 Arena.
After another impressive season, which will end with Djokovic the world’s top ranked player for the second successive year, the Serb now has a chance to cap his campaign by taking the title at the season-ending event for the second time.
The 25-year-old won the Tour Finals in 2008 in Shanghai and he looks in the mood to emulate that success after moving into the final with four consecutive victories — the only unbeaten run of the eight competing players — taking him to 74 match wins in 2012, a record that only David Ferrer has equalled over the last 11 months.
Djokovic had won six of his previous eight meetings with del Potro, but the reigning Australian Open champion had to draw on all his remarkable reserves of energy and determination before finally seeing off the big-hitting sixth seed.
“He was the better player in the first set but I managed to turn it around,” Djokovic said. “I just told myself to stay out there fighting. It’s a step forward because it’s my first final in London. I’ll watch the match this evening and whoever I play it will be tough. It will be an amazing final.”