Resurgent Djokovic leads the way as old guard stays on top

Next Gen poster boy Alexander Zverev's season-ending Tour Finals triumph served up a glimpse into the future of men's tennis although 2018 remained a year dominated once more by the usual, yet aging, suspects as a revitalised Novak Djokovic returned to the peak of his powers.

The Serb tumbled out of the top 10 for the first time in a decade and was ranked as lowly as 22nd in June, slumping to a string of uncharacteristic defeats -- including an embarrassing loss to Italian journeyman Marco Cecchinato at the French Open -- following elbow surgery to fix a lingering injury.

Over the next few months though Djokovic surged back to his all-conquering best, sweeping to Wimbledon and US Open crowns and completing a historic Masters sweep with an elusive victory in Cincinnati.

"There was always part of me that believed I could make it back and I never thought it was impossible," Djokovic said of his climb back to world number one.

"It turned to out to be a perfect five months of the year, with two Grand Slam titles." Roger Federer continued to defy his advancing years as he defended his Australian Open title and then eclipsed Andre Agassi as the oldest top-ranked player in ATP history, at the age of 36.

Rafael Nadal dominated in typical fashion on clay, swaggering to an 11th Roland Garros title, but the injury-plagued Spaniard limped out of two other Grand Slams before further fitness problems curtailed his season.

He played in just nine tournaments, his fewest since 2002, yet still won five titles and compiled a commanding 45-4 record.

- Flushing Meadows meltdown -
=============================
- Halep, Wozniacki end wait -
==============================