Jackson settled for a safety-first approach, winning his sixth successive 110m hurdles race of the season in the comparatively modest time of 13.29sec. Jarrett finished four-hundredths of a second behind him.
The world champion felt a tight thigh muscle before the start and admitted afterwards, 'It made me a bit nervous.' Earlier in the month he pulled out of a race at Crystal Palace with a groin 'niggle'.
This time he also deliberately caused a false start after feeling his watch slipping on his wrist. 'I didn't feel settled and just pushed out of the blocks,' Jackson said. 'I apologised later. Tony said he couldn't remember ever being in a race with me when I false-started.
'I had to run pretty safe, making sure I got out in front and then holding my position. I knew I had it and, taking everything into consideration, I was happy to win.'
The European Championships begin in Helsinki on Sunday week, and Jackson continues the build-up to the defence of his European title in the altitude of Sestriere, Italy, on Sunday, where last year he ran 12.97. He plans to attack his world record of 12.91 in Zurich in three weeks' time.
In the 200m, Britain's John Regis was again beaten by the man who pipped him for last year's world title, Frankie Fredericks of Namibia. This time, however, both were outpaced by the American Michael Johnson, who came back to form with a time of 20.10 - compared to Fredericks's 20.17. Regis clocked 20.31, ahead of Mike Marsh, the 1992 Olympic champion, who finished fourth.
In the men's triathlon, Britain's Simon Lessing confirmed his big- race temperament with a gold in what may be the Games' hardest event of all: a 1.5-kilometre swim, 40km bike race and 10km run.
In another multi-discipline, the American Dan O'Brien goes into today's final day of the athletics programme looking to break his own world decathlon record of 8,891 points, set in 1992. O'Brien's total after five disciplines was 4,736 - 16 ahead of that previous first-day total.
In the women's events Germany's Heike Drechsler won the long jump in the absence of her great rival Jackie Joyner-Kersee from the United States, who pulled out of the competition on Tuesday. Drechsler, the Olympic and world champion, won with a jump of 7.12m.
Mozambique's world champion Maria Mutola proved too strong in the 800m, striding away in the final straight to win in 1min 57.83sec. Diane Modahl, of Britain, came fourth with a time of 1:59.85, ahead of Ireland's Sonia O'Sullivan, who finished seventh in 2:00.69.
Elsewhere at the Games, Puerto Rico made their first world basketball medal a gold by beating Italy 94-80 in the final. Puerto Rico not only reversed an earlier equally decisive loss to Italy, but gave themselves the best possible send-off to next week's World Championship in Toronto. Italy had beaten the United States in the semi-finals. The United States beat Russia 80-71 to take the bronze.
Linford Christie has decided to go straight into his bid for a third successive European Championship 100 metres title without a comeback race. Christie, the world and Olympic champion, who has had a hamstring injury, had been considering a return in Tuesday's Grand Prix meeting in Monte Carlo, where he is training.Reuse content