STUTTGART, GERMANY - VENUS Williams was cool as ice in needing just over an hour to see off German Anna-Lena Groenefeld and reach the second round at the WTA event in Stuttgart on Tuesday.

Williams, ranked eighth in the world, was always in control and kept her 23-year-old opponent pinned to the baseline for large chunks of the game as she strolled to a 6-1, 6-2 win.

But as the Wimbledon champion limped into the post-match press conference with her left knee strapped and ice on her right elbow, she looked far less comfortable before insisting it was just part of her post-game recovery.

'She came out quite aggressive and made me work for the win, it was a good start.'

Williams, 28, will play Kateryna Bondarenko in the second round after the Ukrainian's 4-6, 6-2, 6-1 win over Italian Flavia Pennetta earlier in the day.

'I'll come out and just concentrate on playing my game and look to keep the momentum going,' said Williams.

Earlier, Poland's rising teenage star Agnieszka Radwanska, who reached the quarter-finals at Wimbledon and the Australian Open this year, had few problems as she dispatched Sandra Zahlavova, from the Czech Republic, in straight sets.

The 19-year-old has already won three tournaments so far this season and is on course to meet Olympic champion Elena Dementieva in the quarter-finals, but faces Bulgaria's Victoria Azarenka in the second round.

In the day's other results, France's Marion Bartoli made the second round with a straight sets win over Dominika Cibulkova from Slovakia and will play the winner of Wednesday's clash between Olympic bronze medallist Vera Zvonareva and Daniela Hantuchova.

Russia's Nadia Petrova was never troubled as she saw off Barbora Zahlavova Strycova from the Czech Republic in straight sets 6-2, 6-2 in the final game of the day.

World number two Jelena Jankovic flew into Stuttgart on Monday night fresh from her win at the China Open and although jet-lagged is looking forward to her opening match against Ukrainian Alona Bondarenko.

Jankovic lost this year's US Open final to Serena Williams, but says the experience of reaching her first Grand Slam final has given her plenty of confidence.

'I had my chances to beat Serena in the final, but I was missing some experience,' she said. 'I lost my concentration and didn't take my chances.'

'It doesn't matter, reaching the final game gave me a lot of confidence for the remainder of the season.'

Having struggled with injury for part of the season, the 23-year-old says it is a relief to finally be fit and healthy.

'It is a huge relief to be injury-free, I had an infection in March and I have had concerns about my health the whole time'.

'It affects your fitness so much and you can't train as much as you want. It is so good to be injury free and healthy.' -- AFP