Sean Calvert: Have we seen the best of Andy Murray?

Frustration sets in for Murray

In this week's tennis column Sean Calvert suspects that the heady days of winning grand slams are in the past for Britain's number one...

Andy Murray won his first title since Wimbledon 2013 on Sunday in Shenzhen, but how many more times will we see the Brit get his hands on a major trophy?

When Murray cried those memorable tears of joy on Centre Court at the All England Club after defeating Novak Djokovic to land his second grand slam title how many of us thought he'd wait well over a year to break down with such joy again?

And how many of us thought that his next title would be an ATP 250 in China?

Not many I should imagine and he admitted to being fortunate to take the Shenzhen Open title at all after his opponent Tommy Robredo missed five match points for a straight sets win.

The Spaniard's profligacy combined with a never-say-die attitude from Murray ended the Scot's title drought, but it's clear to most observers that the former US Open and Wimbledon champion is some distance away from the player that won those majors.

Back surgery a year ago was always going to mean that a return to his best form would take time, but a year on and we're not seeing anything from Murray that would make me want to back him to win a major any time soon.

The 27-year-old has always adopted a pained expression on court and was famously labelled a 'drama queen' by Virginia Wade and there's more than an element of truth in that statement, but now the pain seems very much for real.

Sky Sports viewers saw at first hand a microcosm of Murray's season on Tuesday when he played Jerzy Janowicz in the China Open - a tournament that Murray is a 9.08/1 shot to win at the moment.

A terribly slow start saw him go behind 5-1 to the Pole, only to come all the way back to lead 4-2 in the resulting tie break and that's where we saw the frustration about his body's limitations rise to the surface.

A weak serving effort allowed Janowicz back into the breaker and Murray screamed at the top of his lungs that something had "destroyed my serve!"

The inaudible that has damaged his serve so much would have to be the surgery. What else could it be?

It's hard to see new coach Amelie Mauresmo tinkering with Murray's serve to the extent that she's nullified it like Larry Stefanki infamously did to Tim Henman's.

So, we must assume that Murray feels he can no longer do what he wants to on court and there are few more frustrating things for any sportsperson than their body not allowing their talent to flow.

On this occasion against Janowicz the racquet was the thing that was destroyed, but in the great scheme of things it's the serve that's the big issue.

He was able to turn it round against the volatile and unpredictable Janowicz, but the decline this season has been stark, with just four wins in 14 matches against top-20 ranked players and one in seven against top-10 stars.

Some of that can be put down to early season rustiness after the surgery, but the 2014 stats don't lie and Murray is down at 28th in the 'second serve points won' category at the moment.

That's behind the likes of Dudi Sela and Yen Hsun Lu, while Djokovic, Federer, Rafa Nadal, Stan Wawrinka, Kei Nishikori and Jo-Wilfried Tsonga occupy some of the top-10 places.

Bigger servers rule the roost in the 'first serve points won' category, as one would expect, but again, Murray is down in 24th spot behind Robredo.

The Brit was top-20 in each category a year ago and 17th and 11th in 2012, so the decline is as clear on the stats as it is obvious to the naked eye.

It is possible of course to come back stronger from back problems, as Federer has done to great effect and I'm not writing him off as a spent force just yet.

Federer's issues didn't require surgery though and it's not only the serve that's gone awry for Murray in 2014, he looks half a step slower, which means he's not defending as well, which is a big part of his game.

The good news for Murray as far as his ranking for next season is concerned is that he has no points to defend for the rest of the year now, so anything he gets will move him up the table, but he's not sure to qualify for the World Tour Finals by any means.

Currently sitting in 10th spot in the race he can still do it, but based on this season's record against his top-20 rivals he can't be a confident pick to either get there or qualify from the round robin stage if he did qualify.

Perhaps a great off-season working on mobility, flexibility and strength in the back will see him bounce back next season, but at the moment I wouldn't be taking that 9.08/1 on him winning in Beijing.

I still think that the theory about Ivan Lendl leaving when he did has a lot of credence to it in terms of the Czech seeing it as a) job done and b) having doubts about whether Murray could return successfully after surgery.

The 7.413/2 about him winning the Australian Open also looks a lay all day long at the moment and the Specials markets for next season could also be worth a look with a view to backing 'zero' in major wins.

Two grand slam wins in an era containing Djokovic, Federer and Nadal is still a fine achievement of course by Murray and he'll want more, but right now it looks most unlikely.

I hope he can prove me wrong.