Djokovic, who had lost to former World No 1 Roger Federer in the group stage, was under pressure going into the match as he had to secure a set against Berdych to advance to the semifinals.
However, Berdych wasn’t able to put Djokovic to a stern test as the Serbian eased to a win in under 90 minutes.
Djokovic is vying for his fourth consecutive Tour Finals win.
Nadal had already booked his place in the semi-final with one match in the group stage left. He has recently struggled with injury and form but has shown signs of resurgence, particularly in his match against world No 2 Andy Murray who was crushed 6-4, 6-1 on Wednesday.
The other semi-final will feature Federer and the winner of the Murray-Stan Wawrinka match. On Thursday Federer defeated world No 8 Kei Nishikori in three sets 7-5, 4-6, 6-4.
Speaking about his match against Nadal, Djokovic said “We have played so many times and even a couple of times on this very court.”
“He has played great in his first couple of matches and hopefully I will be able to play my best. That is what is needed to beat him."