New brooms ready to brush aside the old guard – or are they

Assuming the rain stays off, there will be four former world No.1 players in action today (plus Maria Sharapova, who last month regained the top spot) and two former holders of the Venus Rosewater Dish. But in south-west London circa the summer of 2012 it seems wisest not to rush to conclusions. While Rafael Nadal has crashed out of the men's competition, and Roger Federer has been tested to the full, most of the big hitters in the woman's game have not entirely convinced either. This year's contest is shaping up as one of the most open for years.

The supporting cast includes the world No.3 player, Poland's Agnieszka Radwanska, an unlikely Kazakh and Italian challenge, and a couple of German grass-court adepts in the form of Sabine Lisicki, a semi-finalist here last year, and Angelique Kerber, the world No.8. Also in the last 16 is Tamira Paszek, of Austria, who has disposed of former world No.1 Caroline Wozniacki, and won the grass-court tournament at Eastbourne a fortnight ago, beating Kerber in the final. The credibility of Lisicki and Kerber's credentials to follow in the footsteps of Steffi Graf will face the acid test this afternoon, when they face Maria Sharapova and Kim Clijsters respectively.

Lisicki was a wildcard when she made it to the semi-final – the best performance from a wildcard at Wimbledon – and in today's match on Court One she will confront the woman who stopped her in her tracks. Despite the German having chances, Sharapova eliminated her in straight sets 12 months ago and earlier this year snuck past her in three sets in Australia. Theoretically, the Russian by way of Florida should be bolstered by completing her own 'Maria slam' at Roland Garros last month as she aims to reclaim the title which she won here as a 17-year-old in 2004. But, perhaps partly due to the windy conditions, those uncertain serve mechanics have not always functioned smoothly, with double faults creeping into her game at points of stress. Lisicki, who has a record of complaining about the amount of noise her opponents make on the other side of the net, will hope to ratchet up the stress levels of her opponent this afternoon. "I know what to expect and how she plays, how it feels to play her," Lisicki said. "I just have to go for my shots and not make too many mistakes."

Arguably more convincing in the opening rounds, and possessed of an even more beguiling storyline, is Clijsters. The likeable Belgian has never won Wimbledon – one of two majors she has not lifted – and this will be her last visit to the All England Club for the championships. Despite a couple of comebacks already, Clijsters is dogged by a stomach problem and plans to hang up her racquet after this autumn's US Open. She may have missed months of the season through injury, but Clijsters has confounded the odds before – when taking the 2009 US Open as a wildcard and new mother. First, however, she must get past the left-hander who is one of the fastest-improving players on the circuit.

"She's a fighter and a physically strong girl, so it will definitely be a very tough match for me," Clijsters said. "But I think with anybody in the draw now, there's a danger. I'm excited I made it into the second week. There's definitely been moments where I think like, oh, I'm going to take a good look around; I'm going to take these emotions in."

Serena Williams should be okay against Kazakhstan's Yaroslava Shvedova – the lady who won a set without permitting her opponent a single point – but the four-time winner is another who can be filed under the 'must do better' category. A few points here or there could have led her to exit the competition at the hands of 2008 semi-finalist Zheng Jie rather than come through 9-7.

Having said all that, although seven grand slams have come and gone since she last won a major title, it would still hardly be a surprise should she lift this one.

If the knack to winning grand slams is to get better each round, then last year's winner Petra Kvitova and Australian Open champion Victoria Azarenka are players to keep an eye on. Kvitova had a false start against Akgul Amanmuradova in the opening round but the comfort of her victories over Elena Baltacha and Varvara Lepchenko suggests she may be hitting last year's form.

"When I came here, it wasn't really confident to play on the grass as I lost my first match in Eastbourne and I played so badly," she said. "But every round I've played better. This year it's a very open tournament."

Azarenka lost in the semi-finals last year but since then the Belarusian has had her great leap forward. At the start of this year she went on a run of 26 victories which earned her wins in Sydney, Doha, Indian Wells, and the Australian Open, which was the best sequence of any on the women's tour since Martina Hingis in 1997. This could also be her year at SW19, but first she faces an intriguing contest against a fellow former world No.1 in the rejuvenated Ana Ivanovic who, under the coaching of Andy Murray's girlfriend's father, Nigel Sears, finally seems ready to build on her 2008 French Open triumph. Three Italians have reached the last 16 but all may well be heading home by close of play today. Kvitova should have too much for Francesca Schiavone, Agnieszka Radwanska has never reached a grand slam semi-final but should overcome Camila Giorgi, and the same applies to the dangerous Paszek against Roberta Vinci. But this is Wimbledon 2012, where it pays to be rather more circumspect.