Jonathan Rea won the first World Superbike race at Buriram by six seconds, as Chaz Davies finished behind him in second for the third consecutive time this season.
Starting from pole, Rea had a strong getaway to lead off the line, and he never gave up first place during the 20-lap race.
Marco Melandri initially kept up with the Northern Irisham, but soon fell behind and came under pressure from his Ducati teammate Chaz Davies.
Davies managed to take second from Melandri but, by the time he took the place, Rea was out of reach, as the gap was over five seconds.
Melandri was also passed by Sykes on the final lap to settle for fourth and secure pole position for Race 2 on Sunday.
Yamaha duo Michael van der Mark and Alex Lowes took fifth and sixth respectively, the former making a move on the latter on Lap 3.
Eugene Laverty (Aprilia) was nearly further 10 seconds behind in seventh but the Irishman ended up retiring on the final lap, handing the position to Jordi Torres (Althea BMW).
MV Augusta rider Leon Camier and the Honda duo of Nicky Hayden and Stefan Bradl completed the top 10.
Race 1 results
|5||Michael van der Mark||Yamaha||11.384|
|8||Leon Camier||MV Agusta||31.755|
|16||Alex de Angelis||Kawasaki||57.203|
|17||Riccardo Russo||Yamaha||1 lap|
|18||Ondrej Jezek||Kawasaki||1 lap|