He went into the third race tied on points with Aucklander Jennings but with the clear advantage of starting six positions ahead of Jennings and also ahead of the other drivers within striking distance on points.
There was close call early in the third race when Osborne was three wide and squeezed against the front straight wall and he avoided a multi-car pile-up to finish sixth and with a 5-point margin over Burson.
"The key is definitely my pit crew," said Osborne afterwards.
"The second race was my best one. That was my closest start to the front and I knew I had to win that race."
An after-midnight, three-way run-off saw Hawke's Bay racer Steve Flynn clinch third place ahead of Ben Harding (Auckland) and Paddy North (Blenheim).
The event started strongly for the six-strong Baypark contingent in the finals with Tauranga's Terry Corin and Dean Waddell finishing first and second in race one. Waddell was the victim of a second-race crash and Corin was side-lined in the race three pile-up.
For Tauranga racer Wood the return to the tricky Central Otago oval again delivered Sprint Car gold.
In a near-duplicate of his 2010 victory, Wood was top qualifier and led the 25-lap final from the start, also setting the fastest lap of the race and finishing 2.4secs ahead of former champions Dean Brindle (Hamilton) and Jamie McDonald (Auckland).
Midget car champion Michael Pickens (Auckland) was fourth and California's Jonathon Allard took fifth place. Mount Maunganui's Bradley Tyrrell, the only other Baypark racer in action at Cromwell, was eighth.
"It was all very similar to 2010. They are calling me the 'King of Cromwell,' said Wood, "I was top qualifier but chose to start on grid two because there was a bit more drive in the track out wider.
"I got a good jump on Brindle and then there was caution on lap two and for some reason they went back to original grids so I had to do it again.
" ... The car set-up let us take higher line through the tight turn one and two and get around the lapped cars."
While there were many similarities in the style Wood won the title, he was racing a new combination.
"We switched to a Maxim chassis this year and three meetings ago we changed to a Kriner Chevy engine which has got really good response from lower revs for the starts."
Both new champions will be in action at the next Baypark meeting on February 1 which is a double-header with the North Island Sprint Car Championship and the second round of the Burger King Pro Dirt Super Saloon Series.
There's another chance at national title success for Baypark racers this weekend with a strong contingent of local Saloon Car racers heading to Stratford for the New Zealand Championship.
The Saloon Car 30-lapper at Baypark on Saturday night was won by Tauranga's Chris Cowling who led home former national champ Brent McClymont (Tauranga) with early leader Paul Cressy (Matamata) taking third place.