TENNIS Alexander Zverev upset Novak Djokovic to claim the biggest title of his career with a 6-4, 6-3 victory Sunday in the ATP Finals at London.Zverev, 21, became the youngest champion of the season-ending event since Djokovic claimed the first of his five titles a decade ago, and the first from Germany since 1995. The top-ranked Djokovic was attempting to tie Roger Federer’s record of six titles but followed the same path as Federer, who lost to Zverev in the semifinals. GOLF PGA: Charles Howell III made a 15-foot birdie putt on the second hole of a playoff with Patrick Rodgers in the RSM Classic at St. Simons Island, Georgia, to end an 11-year victory drought. Howell dropped to his knees and buried his head in his hands, then tearfully embraced his wife and two children. He earned $1,152,000 and a return trip to his hometown of Augusta, Georgia, in April to play in the Masters for the first time since 2012. LPGA: Lexi Thompson shot a final-round 70 to finish at 18-under 270 and win the season-ending CME Group Tour Championship by four strokes over Nelly Korda at Naples, Florida. The win makes this the sixth consecutive year that…