The Ulster Grand Prix ran into severe problems when attempting to stage the first night's practice for Saturday's race.
Torrential rain flooded the circuit after only four practices had been staged and these were for newcomers and the Dundrod 150 which is due to take place tonight.
Officials made valiant attempts to clear the course of water but their efforts were to no avail as even parts of the tarmac which had recently been re-laid lifted under the deluge.
The road services performed a Herculean task attempting to have the course ready for racing but they faced a losing battle and after the first classes had been complete taking up one-and-a-half hours the rain came on in earnest and the superbike riders who were on the starting line-up were told to leave the track because of the downpour.
Clerk of the course Noel Johnston was forced with a difficult decision but eventually it was decided to run the classes which hadn't taken place because of the weather in 'controlled' practice behind travelling marshals. This continued until it was dark
A decision about today's practice and the Dundrod 150 road race will not be made until as late as possible.
Meanwhile in the 125cc class Ian Loughar was fastest at 106.98 followed by Nigel Moore on 105.58 and William Dunlop on 105.27.
The lightweight class for the Dundrod 150 was held concurrently and was topped by Lee Hill on 105.88 then Lee Vernon on 105.41 and Alan Brown 104.80.
The Dundrod National and Challenge classes were held together and led by Mike Pearson on 115.87. Paul Shoesmith was second on 115.58 and Kenny Edwards was third on 113.08.
Today's programme starts with practice for the Ulster Grand Prix Superbike then Supersport then 250cc and Superstock. However there may be extra practice periods because of the curtailment of last night's session.
If everything goes to plan the Dundrod 150 National race will be held starting at 2.50pm followed by the 125cc and Lightweight Supersport run concurrently then the Dundrod 150 Challenge and finally the Dundrod 150 Superbike.
Roads are expected to open tonight after racing at 7.30 pm.