Northern Ireland’s Jonathan Rea tightened his grip on the World Superbike Championship with a double success in Assen.

Welshman Chaz Davies finished runner-up behind Rea in both races at the 4.542-kilometre Cathedral of Speed.

Rea's Kawasaki Racing team-mate Tom Sykes had started on Superpole, but faded in each of the races to finish fifth.

In Sunday's opening race, Rea set a new lap record on the penultimate circuit to record his sixth win at Assen and the fifth of his 2015 championship campaign.

Pata Honda rider Michael van der Mark became the first Dutch man in the history of the World Superbikes Championship to make the podium when he edged out Aprilia Racing's Leon Haslam into fourth.

Rea continued his dominance in race two to stay clear of trouble, while van der Mark again got ahead of Haslam around the penultimate corner to claim another third-place finish.

Spanish rider Nico Terol, of Althea Racing, crashed on lap four and was taken to hospital for checks after a wrist fracture.

The double victory means Rea now leads the championship standings by 50 points on 190 from Haslam, with Davies back on 123.

The World Superbikes Championships moves on to Imola next month.