Federer enjoying himself now, leaping high to his left to angle away a dreamy angled volley cross-court. He adjusts his white bandana, flicks away a stray lock of hair and stares moodily into the middle distance.

Of the four former Wimbledon champions to grace the grass of the All England Club today - Roger Federer, Rafael Nadal, Serena Williams and Maria Sharapova - who is the greatest? You can vote via the panel to the right of this live text commentary. The vote closes at 16:00 BST.

Also send in your thoughts via Twitter, using the #bbctennis hashtag or by texting 81111 (UK only), remembering to tell us WHY you think they are the greatest. It may be a particular stat or moment in their career. And please do put your names on those texts.

Tim Henman
Former British number one on BBC TV

"I think on grass Federer is still a real threat. He remains a contender. I would give him a chance this fortnight because of the way he still moves."

Delightful forehand from Federer, opening up his body and finding both fearsome power and sweet accuracy to pinpoint Lorenzi's backhand corner. Second break of the set taken; less than 50 minutes gone, but the plot already set.

Martina Navratilova
Nine-time Wimbledon singles champion on BBC TV

"That wave to Marion Bartoli at the end was a nice moment and a classy gesture from Sabine Lisicki. She knows that Bartoli was the rightful heir to this match. There were slight nerves early on, but she held her serve, settled down and finished with a very solid 6-2 6-1 victory.

"It was a good start for Lisicki, considering there was some uncertainty in the lead up to the tournament - with getting hurt at the French Open and not playing any warm-up games. But her serving was good, she's moving well and I like the variety in her game."

Sabine Lisicki, speaking to BBC TV's Phil Jones after beating Julia Glushko 6-2 6-1: "It was such a huge honour to play out there in the first match. I was very thankful for that and for the support of fans.

"It was a very special moment at the start; it was great to see Marion Bartoli out there and to have the chance to pay tribute to Elena Baltacha as well. When I stepped out on to court, I was quite nervous but the crowd helped me settled down. This is such a special place; it gives me confidence and I always enjoy playing here."

Sabine Lisicki gets a standing ovation as she seals a 6-2 6-1 victory over Julia Glushko in just 57 minutes. Britain's Andy Murray practised for longer than this morning.

Ordinarily, Centre Court would empty after a match as fans grab the chance to stretch their legs, top up their glass or get a bite to eat. But a certain Rafael Nadal will be gracing the most famous patch of grass within minutes so most are staying put.

Hold to love from Roger, and in the posh seats, Lorenzi's coach Claudio Galoppini sighs a sigh so heavy you can almost hear it hit the floor.

Roger yet to change expression in this entire contest. He may not even realise he's playing tennis - another break so untroubled that he may as well have played it from a deckchair on the baseline.

Image source, Reuters

It's heaving over at Henman Hill, Murray Mound or whatever you'd like to call it. With Rafael Nadal set to grace Centre Court shortly, Roger Federer in action on Court One, and Britain's Heather Watson in action later on court two, a spot on the grass in front of the giant screen would do just nicely.

Tim Henman
Former British number one on BBC TV

"From what I hear about the training camps Federer has been doing he has been working very hard. He knows that if he isn't improving he is going to get left behind. He still has a massive passion. There has been a lot of talk about should he retire. But as long as he has got a passion I think he should play for as long as he can."

Something of a long-haired Steve Buscemi about Lorenzi, perhaps from the Big Lebowski period. Federer, a dude in very much a different way, canters through his own service game with a hold to love.

Jarleth Eaton:, external Watching Roger Federer is one of life's absolute joys. Elegance personified.

Sinead O'Rourke:, external Slow motion Federer action set to some classical music please.

Josh Billig:, external Fed playing a young Steve Buscemi here.

Mrs Federer, Mirka, smiling in the VIP slots as her husband works a pair of break points. No sign of the double doubles, the two sets of twins the couple have produced. Lorenzi with some dash and dare, coming into the net, chasing down one drop shot, stepping across to ping a forehand volley cross-court to rescue the game. Well played sir.

Image source, PA

As the restaurants start to empty post-lunch, Centre Court starts to fill up. Those just strolling into this magnificent court are just time to watch Julia Glushko serve to stay in the match against last year's runner up Sabine Lisicki, the 19th seed.

Martina Navratilova
Nine-time Wimbledon singles champion on BBC TV

"Julia Glushko is trying to get herself organised against Sabine Lisicki. There have been too many unforced errors from her so far. I don't know if Glushko's got a Plan B. She needs to take a little bit of pace off her shots and try to get Lisicki on the run.

"Lisicki looks as if she's enjoying herself out there, but I don't think Marion Bartoli will have any regrets about retiring as she watches on. Bartoli's body was talking to her too much - and it takes a lot of joy out of the sport when it hurts to warm up."

Mike has been released for a spot lunch so it's Lawrence in hot seat alongside Tom, who is guiding you through Federer v Lorenzi.

Agnieszka Radwanska is in a hurry out on court two, the fourth seed leading 6-3 3-0 against Andreea Mitu. The winner plays Australia's Casey Dellacqua.

Tim Henman
Former British number one on BBC TV

Image source, Getty Images

"I'm sure there would have been a few early nerves for Federer but taking the first set 6-1 he'll be very happy to build on that."

Tracy Austin
Two-time Grand Slam champion on BBC Radio 5 live

"Lorenzi does not have a huge serve. It's one Roger has no problem getting back deep - then the rallies start and Lorenzi is in trouble. What Lorenzi has to do is match his skill set against Federer's and ask: 'Where can I make a dint in his game?'"

Unexpected hiatus to the steamrollering as Federer absentmindedly punts two forehands long. A break point for Lorenzi, snuffed out by a brace of whip-crack Fed forehands, and an ace down the middle completes the surgery.