Djokovic opens in style, Wawrinka wins at Finals (Yahoo Sports)

LONDON (AP) — Two-time defending champion Novak Djokovic extended his indoor winning streak with an impressive 6-1, 6-1 win over Marin Cilic Monday in his opening round-robin match at the ATP World Tour Finals, after Stan Wawrinka put his recent struggles behind him with an equally comfortable victory.