Roger Federer took a clinical win over long-time arch rival Novak Djokovic in London, reaching his 16th semifinal out of 17 appearances at ATP World Tour Finals.
The defeat also meant that Djokovic could not challenge Rafael Nadal's world number one position, seeing the Spaniard finishing as year-end world number one for the fifth time.
Ahead of the 49th encounter between the two great players, Djokovic held a 26-22 advantage and won the last five meetings, including their five-set final at this year's Wimbledon Championships, Xinhua news reports.
But Federer dominated O2 Arena's indoor court on Thursday night, breaking Djokovic three times and only facing break point once. The Swiss legend wrapped it up 6-4, 6-3 after 73 minutes.
"I played incredibly, and I knew I had to because that's what Novak does and I was able to produce. So it was definitely magical," Federer said.