US Tour: Swede Mathias Gronberg, called in when Nick Faldo withdrew because of an illness in his family, made the most of the opportunity when the Honda Classic began in Florida yesterday.

Three days before his 36th birthday Gronberg returned a five-under-par 67 on the Mirasol course in Palm Beach Gardens and shared the early first round lead with tournament favourite David Toms, Japan's Ryuji Imada, and World Matchplay champion Geoff Ogilvy from Australia.

Defending champion Padraig Harrington, meanwhile, opened with a 71 - two better than his start a year ago, but eight more than his closing round then - and Ian Poulter and Brian Davis could do no better than 75 and 76 respectively.

After finishing only 160th on the US Tour last season Gronberg survived the qualifying school by the skin of his teeth, but so far this year has made only one halfway cut in four starts.

Gronberg, winner of the European Open by a massive 10 shots at the K Club eight years ago, followed birdies at the first, fifth and sixth by hitting his tee shot to five feet on the short eighth and then almost holed a bunker shot at the 588-yard 12th.

He did bogey the 16th, but was on in two on the 556-yard next and two-putted for his sixth birdie.

Toms and Harrington were playing partners and Harrington was much the faster out of the blocks with two birdies in the first three holes of the inward half.

Then came a double-bogey six on the 16th, however, and he did well to avoid another on the 18th, sinking a 10-foot bogey putt after driving into water and hitting his third into a greenside bunker.

Although he added further birdies at the fifth and sixth, the two par fives on the front nine, Toms completed a run of five successive birdies on the same two holes.

The American is the only world top-10 player in the field, already has a win to his name this season and last Sunday was joint runner-up to Tiger Woods at the Ford Championship in Miami.

Poulter, trying to climb from 65th in the world back into the top 50 in time for the Masters next month, double-bogeyed his first hole and had another on the 16th, his seventh.

He did make four birdies, but there were also three bogeys in an erratic display.

After a promising joint seventh place at Pebble Beach last month Davis is now in danger of a third successive missed cut, the most damage coming when he double-bogeyed the short eighth.

CHALLENGE TOUR: Ireland's four European Challenge Tour representatives will be fighting to make the halfway cut at the Tusker Kenya Open today after a disappointing first round saw John Kelly as the best placed Irishman in the field at three over par.

Eamonn Brady (five over), Justin Kehoe (five over) and Tim Rice (eight over) face an uphill battle to feature in the weekend action at the Karen Golf Club on the outskirts of Nairobi.

While the Irish were struggling, Scotland's Andrew McArthur continued his blistering start to the season by moving into a share of the lead,with Johan Axgren of Sweden.

The Glasgow golfer, in his rookie season as a professional, made a great start to the year at the five tournaments in Central and South America.

He continued that rich vein of form at the Karen Golf Club yesterday, posting an opening score of six under par 64 to join Axgren atop the leaderboard.