Determined Djokovic edges longtime rival

World No 1 reaches eighth US Open semi in a row with win over Murray

Through a pair of back-and-forth sets, Novak Djokovic and Andy Murray put on a display befitting a matchup of past US Open champions.

They tracked down would-be winners and somehow got them back, prolonging points that involved 10 or 20 strokes or more, extended by Djokovic's slides and splits or Murray's gifted anticipation. After one 30-shot masterpiece on his way to victory, Djokovic raised his right fist, bellowed, "Come on!" and windmilled his arms to rile up the crowd.