Marin Cilic

The World Number 8 Croatian player is a big name on the circuit for quite some time now. Marin Cilic has been known to cause a lot of upsets in the past. His career has been illustrious with Finale finishes in all the Grand Slams except the French Open. He is the only player on this list who has won a Grand Slam when he bagged the US Open title in 2014. He has faced off with Roger Federer in Wimbledon and the Australian Open finals and given a strong performance. Given his numbers and his focus, Cilic is sure to cause a disturbance in the Big Four dominance soon!
The 30-year-old player has quite a few mean and sleek shots up his sleeve which makes him a formidable opponent too. The upcoming season should have Cilic pushing for more and it won't be surprising if he does manage to go get it!