Top-5 rankings in mind, Croatian Cilic ready to challenge Big Four for Slams this season

'Goran had quite a big influence on me to change my mentality and focus on my game. He changed my serve, I started to get aggressive and that is what I needed in my career'

Terming the surprise loss against little known Jozef Kovalik as "small stumble", Marin Cilic says he is ready to challenge the 'Big Four' in the 2017 season since he has taken a "huge step forward" with new coach Jonas Bjorkman on the motivational front.

World number six Cilic suffered a shock defeat against the little-known Slovakian, ranked outside the top-100, who entered the season-opening Chennai Open via qualifiers.

28-year-old Croat savoured success in the 2016 season as he beat Novak Djokovic in the Paris Masters quarter-finals and also captured the Cincinnati Masters defeating reigning World No 1 Andy Murray.

Talking about the positive influence the Swede has on his game in the first six months of joining his team, Cilic said the motivational level has not dropped since Bjorkman started working with him in August, 2016.

"There are parts in my game that I felt clicked right away, when we started to talk about certain things, about improvements in my game. Also, motivational part was a big step forward for me, in a way to have more positive energy while coming for the matches. Motivation was high, matches after matches, overall in my game. I am constantly playing at a good level. That is helping me to be more aggressive on the courts," Cilic said in an exclusive interview with PTI.

Asked to elaborate, Cilic chose to keep the talks between him and Bjorkman as secret.

"Obviously I am not willing to share those."

Asked if he feels confident enough to take on the Big Four -- Djokovic, Murray, Roger Federer and Rafael Nadal -- at the Grand Slam level, he said, "I hope so".

"You never know what the year is going to bring but looking at this upcoming season, I am feeling quite good. This loss is a small stumble but I believe I have the capabilities to be in the top-5 for sure, it's definitely going to be a challenge, and I am ready for it."

Cilic, who rose to career-best World No 6 last season, said he had very a fruitful time with previous coach and fellow Croatian Goran Ivanisevic.

"Working with Goran was successful. Goran had quite a big influence on me to change my mentality and focus on my game. He changed my serve, I started to get aggressive and that is what I needed in my career. I had great result in 2014 which showed I am capable of winning those big tournaments," he said referring to his maiden Grand Slam trophy at the US Open.

Cilic also spoke about the similarities between the 2014 season when he won four titles, including three ATP250, and a successful 2016.

"In both these years I was playing quite consistently and on a good level in big tournaments. In 2016 I had more results consistently at the higher level and 2014 I played really well in the second part of the year. That consistent play was my big focus in this second part of 2016, to keep the mentality strong, fresh and motivated for the matches.

"These seasons are very long, you are at different places week after week. The motivational part is key for success," he said.

In a recent analysis it was revealed that in the last two seasons Cilic was up 40-0, 460 times and he won them all.

In 2016, when he was up 40-15, out of 324, he won 323 and even when he was 15-0 up, his winning percentage was 92.

"Quite interesting statistics. For sure, I am relying a lot on my serve. In the match against Kovalik also my second serve percentage was 36 and usually during the year I am 50 on second serve returns, that already shows that on that part of the game I was not doing well.

"That is one of the key parts of my game that I serve well. Return games I guess cost me the match," he said.

Asked if his height (he is 6'6" feet tall) makes it difficult to pick low balls and half volleys, Cilic replied: "The good part of my game and my physically abilities is that I am a naturally good mover. Even though I am quite tall, may be I am above three-four guys of my height as a great mover. I am not comparing myself with Novak or Andy Murray. They are a bit shorter than me.

"In certain situations I am trying to adapt. Kovalik was also hitting flat, low balls, I had to adjust and be prepared for any kind of a game. That's why tennis is such a great game that not only a big server is going to succeed, or hitting big will win you the games but variety in the game," he said.

"I am training on everything. In the gym I work out quite strong because of that good training I am feeling quite strong and flexible on the courts."

In 2016, Cilic lost three big matches, including the fourth rubber of the Davis Cup final against Argentina's Juan Martin Del Potro, when he was up by two sets to love but eventually lost the tie.

Cilic said he approaches difficult losses from his own perspective.

"Some people approach desperately, negatively. It was a tough loss for me too, it was and opportunity for us to win. I know I gave whatever I had. I know that I had won seven matches in a row before that and being in the final and part of those great stories is extremely a positive experience. I don't want to put negative part and put myself in big hole just because of that loss.

"I know that I played well, I lost to a player, who played amazing match. That was just unfortunate to come at times," he concluded.