Nick Bollettieri: Murray has extra firepower to dodge cagey Croat's bullets

(PA)

Another round and another step up for Andy Murray. Ivan Ljubicic is a cagey old pro, he's done his court time and knows his game, although there is something that doesn't add up with the Croat.

Ljubicic's record here doesn't make sense for a guy whose game is based around the serve. This is his 11th Wimbledon and only twice before has he made it beyond the second round. The norm here in the first few days is in favour of the big servers with the courts slick and well grassed and the bounce on the low side. Maybe he just doesn't like the grass.

The guy is a server, though, and this match will boil down to one area; Ljubicic's serve against Murray's return. Ljubicic has to serve well. In his opening matches his stats for his first serve (at 57 per cent and 65 per cent) are not going to make you stop and think "whoa, this guy is dangerous". They are heading in the right direction but they have to keep climbing.

I'm liking what I'm seeing with Murray. Let's deal with what some people call his attitude. You know what I say? Don't make him stand in the corner like a bad boy. Sure he moans and groans, but don't try and curb him. He will never be a momma's boy, he is his own man. If I coached him I'd let him talk – I spoke with Boris Becker about this and he agrees. Let him voice his frustrations as long – and here's the key – he lets go of the last point with his last yell and gets right back in the game.

Over the last few weeks, since Paris began, Murray has been moving well. On Wednesday, after his win against Tobias Kamke, he said he could have moved better against the German, but he should not worry. He's in a good place. He is becoming the all-round player. His return of serve is getting better and better and if that is in good working order today, then, holy cow, Ljubicic is going to have to send down bullets.

Murray has always been a good counter-puncher but you need more to get those big trophies up on your shelf. Now he's starting to add extra firepower, that serve has juice, the forehand is bigger and what I like – this is one of my themes – he's getting closer to that baseline.

So what does the big Croat have to do to upset Murray? He certainly won't be overawed on Centre Court. This is a guy who has been a pro for 13 years and has been as high as No 3 in the rankings. He has a decent record against Murray – winning their last meeting last year – but they have never met on grass. You only have to look back to Indian Wells last year for an example of what Ljubicic is sometimes capable of; he beat Rafa Nadal and Novak Djokovic on the way to winning the whole damn tournament.

Ljubicic is a hard man – I'm talking surfaces here, guys – and does not feel as comfortable as Murray on the grass, nor does he have the form the Brit does on this surface. It means Ljubicic, who, don't forget, had a good first-round win over the seeded Marin Cilic in round one, has to get that serve at its very best. Hey, why not throw in some serve and volley? That would surprise his opponent. Get off that baseline, boy, and force Murray to try and pass.

But Murray's the man here – it's tough on Ljubicic but it's difficult to see it any other way. Murray's a confident guy at the moment. Sure he still has those sparks where he rants away to himself, but you know what? So what.

Today's big match: Andy Murray v Ivan Ljubicic

How they match up:

Scotland Nationality Croatia

24 Age 32

London Residence Monte Carlo

Right-handed Plays Right-handed

6ft 3in Height 6ft 4in

4 World ranking 33

17 Career titles 10

$16m Career prize-money $9.8m

W21 L5 Wimbledon record W8 L10

Semi-final (2) Wimbledon best 3R (2)

W3 L3 Head-to-head W3 L3

1-8 Odds 8-1

Bollettieri's prediction: Murray in four

Del Potro's long reach makes him a dangerous dark horse

Argentine impresses in winning large v little battle with Rochus

I watched Juan Martin del Potro and Olivier Rochus come out on to court yesterday and have you ever seen anything like it? Rochus only came up to about Del Potro's ass. Officially there's a foot between them – 5ft 6in to 6ft 6in – but in the flesh it looked more. Rochus resumed a set up but Del Potro blew him clean away. Pow – serve after serve. The big guy has had problems with his fitness but I've been pretty impressed with his two matches so far; he is a danger (if he really is fit enough).

Del Potro's size brings him one noticeable advantage – this also has plenty to do with his ability, too. His reach enables him to hit returns above his shoulder on his back-hand and that is a real weapon. He looks like he's getting back into the swing of things and here's a surprise, getting to the third round makes this already his best Wimbledon. None of the big boys will fancy coming up against him. He's dangerous.

Serena must come forward more after struggling against Halep

Boy, yesterday down here made a can of sardines look roomy. I was walking back through the crowds from Court Two, gathering my thoughts on Serena Williams' match against Simona Halep, when somebody grabbed me. It was Serena. She had been walking back from the court too, spotted me and gave me one of her big hugs. She wasn't too happy with her game, though.

Halep tested her. Serena said her serve was tough to deal with in that first set. Halep's only a little girl so for her to do that against someone of Serena's stature, well heck, that should give encouragement to smaller players up and down the land. I was amazed at her power – she's not 20 yet and I reckon she has a real bright future. One to watch, guys.

As for Serena, she's got to get forward. Get herself in front of the baseline and say to her opponent, "Hey, do you know who I am?" I got asked yesterday to separate Maria Sharapova and Serena. These two are among the most competitive players I have ever known. If Sharapova gets her serve right she can test anybody, but Serena has more ammunition. But let's wait and see on that one as they can't meet until the semis next week.

Mr B's A-Zee

I is for indoors And boy have we needed the great indoors at times this week. Centre Court under the roof is a whole different experience but it's one I've got a suspicion may be to Andy Murray's liking.

J is for John And there is only one John when it comes to Wimbledon. McEnroe is now a great commentator on the game over here but back home he's one of the guys trying to put some stars back into Stars and Stripes tennis.

Win a week at my academy

Want a week's tennis holiday at my IMG Nick Bollettieri Academy in Florida? Included in the prize is five days' top-class tuition.

The prize can be for an adult wanting to shape up his or her game, or for a child who wants to follow in the footsteps of the likes of Andre Agassi, Monica Seles and Maria Sharapova, among other players who went from being kids under my tuition to No 1 in the world.

What you have to do is answer this question: Tell me what the score will be in Andy Murray's match against Ivan Ljubicic. Send me your answer (and predict how long the match will last, in case we need a tie-break) to bolly@independent.co.uk and the best one will win a signed hat or T-shirt. I'll be putting out a question every day and all the winners will go into the hat for the big prize to be drawn at the end of the fortnight: a week at the IMG Nick Bollettieri Academy.

Coaching tip of the day

Think ahead. Here's the thing – react from your ball. You know where you are hitting it, so where will your opponent hit it back to you? To work that out, think about where he or she will make contact with the ball and keep a close eye on their racket face. There's your clue. Most players have habits in how they strike it depending on where they are on the court.

Email bolly@independent.co.uk with problems and I'll pick a few out.