Alexander Zverev ‘on top of the world’ after securing No. 1 ranking

Alexander Zverev accelerated his ascent to number one in the world rankings for the first time in his career on Thursday as he beat Tallon Griekspoor 6-4, 7-5 to reach the quarter-finals of the Vienna Open. The 29-year-old German was already assured of finishing the season top of the ATP rankings but, in the absence