World Superbike champion Jonathan Rea was second in race one of the Great Britain round at Donington as Michael van der Mark took his first ever win.
Rea and third-place finisher Tom Sykes diced for the lead in the early stages but Pata Yamaha rider Van der Mark assumed the lead with eight laps to go.
The 25-year-old is the first Dutchman to win a World Superbike race.
Rea must wait until Sunday to try and earn a record 60 series wins, but his championship lead extends to 59 points.
The Northern Irishman drew level with four-time world champion Carl Fogarty on 59 victories by taking a double success at Imola two weeks ago.
The 31-year-old Kawasaki rider will hope to improve that tally in Sunday's race two at the Leicestershire circuit.
The three-time world champion has now been on the podium in six of the last seven races at the Great Britain round, his sole triumph in that time coming last year.
"It was a solid race but Michael's bike had much more rubber left in the latter stages, much more grip.
"I was trying my best in the last two sectors but it was not enough to beat Michael's pace," said Rea, who finished more than a second behind the race winner.
Van der Mark had achieved 14 World Superbike rostrum finishes during his career and was surprised to become the first non-British rider to occupy the top step at Donington since 2012.
"It's amazing. I have been waiting for this for four years and to take victory here is something I really didn't expect," said the former World Supersport champion.
"The boys in front of me made a mistake and I was able to pull away. I had to push a lot in the last few laps though."
England's Alex Lowes finished fourth, with Northern Ireland's Eugene Laverty sixth and Welshman Chaz Davies eighth.
|World Superbike Championship 2018 standings|
|1. Jonathan Rea (GBR)||Kawasaki||229|
|2. Chaz Davies (GBR)||Ducati||170|
|3. Tom Sykes (GBR)||Kawasaki||153|
|4. Michael van der Mark (NED)||Yamaha||138|
|5. Marco Melandri (ITA)||Ducati||131|
|6. Xavi Fores (SPA)||Ducati||124|