SportSelectors back Vaughan's fitnessFingers crossed: With a bit of luck, Vaughan's knee problems will not prevent him going into action against South AfricaDavid Lloyd|Cricket Correspondent13 April 2012England selector Geoff Miller is certain Michael Vaughan will be fit for next week's first Test against South Africa despite fresh concerns over the captain's right knee.Vaughan spent time off the field while playing for Yorkshire yesterday and had ice treatment as Durham wrapped up an eight-wicket win at Headingley.The 33-year-old batsman was seen flexing his knee - which has been operated on four times - during an innings of 72 earlier in the match but chairman of selectors Miller said today: "It's something and nothing. It just gave him a little bit of a niggle but it's all under control."With all-rounder Andrew Flintoff still needing to find form as well as prove his fitness after a side strain, all the signs point to England naming an unchanged team for a sixth consecutive matchVaughan admitted his knee gave him some minor problems during the New Zealand series when three games were crammed into three and a half weeks. His absence this season would almost certainly see Middlesex opener Andrew Strauss appointed captain.South African Martin van Jaarsveld became the first player in Kent's history to score two centuries and take five wickets in the same match as he guided the county to a four-wicket victory against struggling Surrey at The Oval today.Read MoreEngland succumb to spinners in opening ODI defeat to Sri LankaArsenal injury update: Hincapie, Calafiori, Dowman latest return datesEx-Chelsea star set for Premier League return as 'player swap' agreedSponsoredIncredible days out and trips for autumn and winter"I'm completely humbled," he said. "Not in my wildest dreams did I think I would have a match like this. It has to be my No1."MORE ABOUTCricketDurhamHeadingleyYorkshire