A penalty that went wide in the first 60 seconds did not bode well for Thurston and Haverhill went ahead on the half hour, Darren Carew punching a hole in the defence before falling short of the line.
Martyn Hughes picked the ball up, saw the gap, and popped over the line for a try, Kieron Ewens adding the extras.
Thurston replied with a try, although the conversion hit the post, and Haverhill went into the interval ahead.
Haverhill went further in front after the break, Adam Hunt intercepting a chip from Jones and running 40 metres to score. Ewens converted for 14-5.
On 50 minutes, Haverhill’s fitness began to tell and Thurston scored a try through their scrum-half, the extras being added.
Thurston went ahead for the first time in the game on 63 minutes, despite claims that the visiting scorer had been held up on the line.
At this point, Thurston led 19-14 but the defining moment of the game came soon after when Carew was sent to the sin-bin for stamping.
By the time he had returned, Thurston had scored a further four tries to take an unassailable 43-14 lead.
Thurston added one more unconverted try to their tally and, had it not been for some poor passing, they could have scored a lot more.
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