The veteran former grand prix driver Derek Warwick scored his first touring car win for Vauxhall and the series man of the moment, Anthony Reid, in his Nissan, took the other.
Warwick's win came in an extraordinary feature race in which the miserable weather at the Scottish track played a full part.
The track was almost dry when the race started and Warwick was immediately in trouble. Honda's James Thompson had stalled at the front of the grid and, as cars behind swerved, there was a clash in which Warwick was involved. This resulted in his team-mate John Cleland, bravely racing with cracked ribs, being pushed off into the gravel trap and retirement.
Reid had made a great start from pole, but his lead disappeared when the safety car was scrambled to allow Cleland's car to be moved to safety. As the field followed the safety car Warwick pitted twice - once to have body damage patched up and then, as the rain started falling, for deep- grooved wet weather tyres.
For several laps it looked as though Warwick's gamble had failed. The track was not as wet as his team predicted it would become - just yet.
At the front Reid had spun off after contact with Renault's Alain Menu, who moved into the lead.
When the rain became heavier all the top runners headed for the pits and Warwick worked his way into the lead. Of the rest, Rydell and Audi's Yvan Muller timed their stops best, while Menu lost time with a sticking wheel nut.
Before the end, Muller had passed Rydell to take second place - his and Audi's first podium finish of the year. Rydell was third, with Menu fourth and Reid seventh.
Rydell's day had started badly when he was a victim of a first-corner fracas in the sprint race. He then had to watch his three closest rivals in the points table take the podium places.
Reid led throughout from pole position, never looking seriously threatened by the chasing pack, and the Scot went on to take his first ever win on home soil.
Thompson was second from Menu, with Muller providing all the action with a series of sometimes robust moves which took him from sixth place up to third, before a failed challenge for second put him back to fourth.
Rydell still holds the upper hand, but with six rounds left to run, Menu, Reid and Thompson are all still well in the hunt.Reuse content