Eleven-times TT winner Michael Dunlop had to settle for third place in the opening race of the Southern 100 meeting on the Isle of Man.
The 1000cc event was won by Bradford's Dean Harrison on a Kawasaki, with Tyco Suzuki star Guy Martin 5.9 seconds behind in second.
Lincolnshire's Martin had just a 0.4-second lead over BMW-mounted Dunlop at the chequered flag.
Ballymoney's Paul Robinson won the 125cc race.
In the main event, Dunlop had the consolation of setting the fastest lap of the race, achieving an average speed of 113.157mph on his fifth circuit.
That left the 25-year-old marginally outside the lap record he set on the 4.25-mile Billown circuit last year.
Harrison led from start to finish to break the stranglehold which the Ballymoney man had enjoyed in the corresponding race in recent years.
Dunlop was the winner in 2011, 2012 and 2013 but never looked like extending that run after ending the first of the seven laps in fifth place.
He moved up to third on lap two, but was unable to overtake Martin and had to settle for the final podium spot.
"The engine just doesn't suit here - we're developing some stuff on the bike and hopefully we'll continue to make progress through the week," said Dunlop after the race.
Manxman Dan Kneen was fourth on the Cookstown BE Racing machine, with English duo Russ Mountford and Ivan Lintin making up the top six.
Ramsey rider Conor Cummins was the first 600cc rider home on his Jackson Honda.
Racing continues on Wednesday evening and on Thursday, with the main Solo Championship race being held on Thursday afternoon.