Jonathan Rea once again extended his lead at the top of the World Superbike standings with two victories at Assen.

The Kawasaki rider took the chequered flag in both races in Netherlands to take his tally for the season to 190 points, 50 ahead of nearest challenger Leon Haslam (Aprilia).

Rea's performance marked his second double of the campaign having taken a maximum 50-point haul in Thailand last month.

Last year's runner-up and 2013 champion Tom Sykes had taken superpole in qualifying on Saturday, but could only finish fifth in the first race after apparently suffering from a lack of grip as team-mate Rea surged to victory.

The Northern Irishman set a new lap record on the penultimate lap to race away from second-placed finisher Chaz Davies of Ducati.

Michael van der Mark (Pata Honda) became the first Dutchman to claim a Superbike podium by taking third ahead of Haslam.

And the second race followed a similar pattern at the front as Rea again timed his charge to perfection, racing clear with eight laps remaining and holding off Davies to triumph.

Van der Mark took third once more ahead of Haslam and Sykes.