Cork-born Austin O'Connor flies the Irish flag on his own at Burghley this week following the withdrawal of Lucy Thompson, whose back injury is responding to physiotherapy, but not quickly enough to get her back in the saddle in time for the Pedigree Chum-sponsored fixture.

O'Connor, who is now based in Cornwall but has won on what used to be home ground at Blarney Castle for the past two years, is making a belated four-star debut at Burghley. He made an abortive outing to Badminton three years ago, getting as far as the first horse inspection.

This time out he rides Eugene McKenna's Simply Rhett and believes the mare has had the best possible build-up for the big one. "She's had a great autumn, the best ever, so hopefully she'll fly round, but it is a really big track," he said yesterday afternoon after surviving the first hurdle - the dreaded horse inspection, in which New Zealander Joe Meyer was the only casualty when Southern Star was deemed to be lame.

But O'Connor is not the only rider to think Mark Phillips' 35-fence track poses a particularly tough challenge. Olympic champion Blyth Tait, who continued his series of victories by winning the big CIC at Scarvagh House in Co Down last weekend with his Atlanta star Ready Teddy and then rode younger stable companion Eze to win at Springhill back in England on Monday, believes the Burghley cross-country is "enormous."

"It's a real four-star test," he said yesterday. "There are two or three fences that don't ask too much, but everything else is a really big question. I'm not freaking yet, but maybe I will tomorrow when I walk it and it still looks big!"

Tait is favourite to claim the honours in the 63-horse field, having won the British and Scottish championships in the last couple of weeks prior to clinching the CIC series at Scarvagh House. The New Zealander is first into the dressage arena this morning with Chesterfield.