Jonathan Rea won the first race of the weekend at Misano on Saturday to extend his lead over Chaz Davies in the World Superbike Championship to 80 points.
Northern Irishman Rea, 31, led from start to finish on his Kawasaki to take a ninth win of the season and his fifth career success at the Italian circuit.
Ducati rider Davies was less than three seconds behind Rea in second, with Eugene Laverty third on his Aprilia.
After race two on Sunday, the series takes a break until mid-September.
Rea will now hope to repeat the double he achieved at Laguna Seca in the previous round as he continues his bid for a fourth consecutive world title to equal Englishman Carl Fogarty's record tally.
The Isle of Man-based rider now boasts 63 triumphs in the championship and becomes the second most successful World Superbike rider ever at Misano, one behind Australian Troy Bayliss.
Rea was a double winner at the course in 2016 but had to settle for third and second last year.
He was always in control of the first race of round nine, with Davies taking advantage of a mistake by Laverty, when he ran wide five laps from home, to snatch the runner-up spot.
"My team gave me a great bike today and I felt really good out there despite the hot conditions. I was able to ride within myself and not push the boundaries," said Rea.
Laverty's season has been transformed in recent rounds as he has followed up fourth places in race two at Brno and race one at Laguna Seca with two consecutive podium positions.
Davies has been on the rostrum in 11 of the 17 races to date.
Michael van der Mark was fourth, with Tom Sykes and Xavi Fores completing the top six leaderboard and Alex Lowes crashing out.
|2018 WSB Riders' Championship|
|Jonathan Rea (GB)||Kawasaki||345 pts|
|Chaz Davies (GB)||Ducati||265|
|Michael van der Mark (Ned)||Yamaha||228|
|Tom Sykes (GB)||Kawasaki||207|
|Alex Lowes (GB)||Yamaha||183|
|Marco Melandri (Ita)||Ducati||177|