Top 5 players most likely to end the Big 4 domination 

Nick Kyrgios

Australia v USA - Davis Cup World Group Quarterfinals

Ever the man associated with controversies and showcasing the most abrupt and erratic behaviour on tour, the 23-year-old Australian is a bustling house of talent. Nick Kyrgios holds the rare record aside from fellow Australian Lleyton Hewitt to have defeated Federer, Djokovic and Nadal in his first encounters with them! If that isn't enough to indicate his greatness, what is? Due to his on and off time on the court, Krygios is now at World Number 36 in the ATP rankings but nobody can doubt the talent he possesses.

With 4 ATP titles to his name, Krygios, if in stable form, is a force to reckon with. If he channelizes his talent well and brings back the focus he can be a major threat to the Big 4 and who knows, he might even cause a big impact on the Grand Slams.