Tennis: Zverev is looking forward to the responsibility of being the world number one [SOUND]

# Tennis: Two-time Grand Slam champion Alexander Zverev is looking forward to the responsibility of being world number one. The 29-year-old German clinched the honour on Monday. After losing three major finals, he landed his first Grand Slam title at the French Open in June, and followed that with victory at the US Open. Zverev admits the full weight of reaching the top spot has not quite sunk in: