Nystrom fired his 7-under 65 in the morning, before the 29-year-old Owen had even teed off. But Owen birdied eight holes in a 10-hole stretch beginning at the seventh to move into the outright lead before his only three-putt of the round brought him back even with the Swede.
The leading pair was one stroke in front of Ricardo Gonzalez of Argentina --- bidding for back to back wins following his success in the European Masters --- and Australian John Senden.
Owen admitted his British Open experience took its toll mentally. After 35 holes he was leading the world's oldest tournament and at the 11th hole in the third round he recorded a double eagle.
"It was an incredible experience and one I am never going to forget," he said. "It took me nearly a month to come down, but I gave myself a good talking to after missing the cut at the Scottish PGA Championship and my putting's come good again."
At 39th on the European money list, Owen can afford to look forward to his winter break with an easy mind. But Nystrom, in 121st position, cannot relax until his card is secured for 2002.
"I changed my putting at the BMW International Open and my form has gradually come back," Nystrom said. "Basically, I changed everything. I had to as I had been putting horribly."
A dozen players were close to the lead at 67, including Bernhard Langer, Pierre Fulke, Ian Poulter and Jarmo Sandelin, who was in touch with the leaders before dropping two shots in the last three holes.