Joe Yeardsley charged to victory in the Senior Manx Grand Prix race, setting a new lap record in the process.
The Laxey racer shaved three seconds off the lap record on the final circuit with a speed of 122.051mph.
The 26-year-old took the win by nine seconds after a fierce battle with fellow Manxman and newcomer Marcus Simpson which saw three lead changes.
Leicestershire's Daniel Ingham came in third, 33 seconds back, with the top three all on Yamaha machinery.
The race, which had been shortened from four laps to three of the 37.75-mile (60km) Mountain Course, was delayed by five hours due to wet conditions on the roads.
When the race got underway, Yeardsley took a narrow lead in the early sectors of lap one, sitting 0.3 seconds ahead of 24-year-old Simpson at Ballaugh, with Williams a further second behind in third.
But the two newcomers had traded places by Ramsey, with Simpson overhauling Yeardsley to create a three-second lead.
That was extended to 7.2 seconds as the machines pulled into the pits for a mandatory pitstop, with Simpson completing his first circuit at a speed of 120.053mph.
After a quick pitstop, Simpson extended his lead to 8.7 seconds before a charge from Yeardsley saw the gap truncated to 3.9 seconds by the Bungalow on the mountain section of the course, with the time falling further to 2.5 seconds by the end of the second lap.
Although Williams was holding on to third at the end of the lap, 25 seconds back on the leaders, he was facing his own challenge from Melton Mowbray's Ingham, who crossed the line just 2.8 seconds behind.
But there was a change in the order by the time the machines reached Glen Helen on the final lap, with Yeardsley leading Simpson by 2.13 seconds and Ingham slotting in to third, two seconds ahead of Williams, dashing hopes of an all-Manx podium.
In a blistering final circuit of the Mountain Course, Yeardsley had stretched his lead out to 8.4 seconds by the Bungalow.
Yeardsley took the chequered flag with a 9.545 seconds advantage over his fellow Manxman, setting a new Senior Manx MGP lap record of 18 minutes and 32.882 seconds, at a speed of 122.051mph, breaking the previous record set by Stephen Smith last year.
The final lap saw second place Simpson average 120.738mph, and Ingham 120.118, confirming him in third place 6.2 seconds ahead of Williams.
Speaking to Manx Radio, Yeardsley said he was "absolutely over the moon" with the result, which would help to make up for the disappointment of having to retire from the Junior MGP race while in the lead on Saturday.
He said, having started 11th on the road in the time trial, he had gotten "stuck in a lot of traffic" during the race, which had held him up because he was "still learning the course" and where it was safe to overtake.
He said: "You can't just bully your way past here, you've got to respect the other riders."
The result saw Yeardsley emulate his father Buddy Yeardsley's 1985 success in the race as a Senior MGP winner, something he said was "amazing".