Nick Kyrgios was keen to hose down any differences with Rafael Nadal and focus on the task ahead after battling through the longest match of his career.
Nick Kyrgios beat Russia's Karen Khachanov 6-2, 7-6 (7/5), 6-7 (6/8), 6-7 (7/9), 7-6 (10/8) in the third round of the Australian Open.
Novak Djokovic battled past fifth-ranked Daniil Medvedev 6-1, 5-7, 6-4 to send Serbia into the inaugural ATP Cup final.
Rafael Nadal led Spain to the Davis Cup title just over three weeks ago then went on a short break before beginning his preparations for the new season.
Karen Khachanov became the third different first-time winner of a Masters tournament this year - joining Juan Martin del Potro and John Isner.
Rafael Nadal, seeking a 4th US Open title and 18th major, will face Georgia's world number 37 Nikoloz Basilashvili for a place in the quarter-finals.
Novak Djokovic reached the Wimbledon quarter-finals for the 10th time on Monday with a 6-4, 6-2, 6-2 win over Russia's Karen Khachanov.