In the men's final Tearney used his experience to wear down Sisam, completing a 6-4, 6-3 victory in one hour and eight minutes on court.
"It's a nice feeling after the year I've had. Conditions were tough. I am still coming back and not playing my best tennis yet. But I played well today," said Tearney.
27-year-old Tearney won the tactical battle in the first set and didn't allow Sisam to dominate with his trademark forehand.
Both players traded early service breaks before Tearney got the decisive break in the 6th game and went on to close out the first set 6-4.
"The key was to make him volley when he did come in. I just feel like the key difference was a few points and I stayed focused on the big points. He has a big game, a good forehand but I made him play an extra ball," Tearney said.
Sisam had impressed en route to the final with big wins over defending champion Artem Sitak and third seed Olly Sadler, but he couldn't produce the same level in the decider.
He grew frustrated at a mounting unforced error rate and received a code violation for swearing late in the first set. He struggled at the net and numerous missed volleys cost him.
Tearney's greater experience and big match temperament proved the difference and it was a similar pattern in the second set with the players trading early breaks before Tearney took control.
He broke in the fifth game and went on to close out the match 6-3 on his second match point. Tearney earns a wildcard into ASB Classic qualifying next month. However it wouldn't be a surprise if Sisam is also given a qualifying wildcard into the ASB Classic given his performance this week.
"It was a great week," Sisam said.
"I came into the tournament not knowing what to expect. Today it was down to a couple of points. I missed a smash and some volleys on some big points and if they had gone my way anything could have happened."
Sisam would relish the opportunity if given a wildcard into the ASB Classic.
"If I got a chance to play against the best guys that's what you want."
But first Sisam has the 18's Nationals next week. He plans to play qualifying at the junior Australian Open and some futures tournaments in Asia in the early part of next year. He is hoping to get into a US college next year before turning pro.
"If I do that I will have a back-up in case tennis doesn't work out," Sisam said.
Tearney had spent the past six months sidelined with a herniated disc in his back and has recently been coaching in Wellington.
His form this week has restored his confidence and his desire to perform at next month's ATP tournament in Auckland.
"In some ways I am just seeing how my level is and it's not there yet but I am hoping it will come and just want to get on court next week and practice," Tearney said.
The women's contest was tight with Jones prevailing in an hour long opening set against the tenacious Melbourne based 24-year-old. The two baseliners had some terrific rallies in the first set.
Jones raced to a 5-2 lead in the second set but Westbury refused to lie down and fought back to level at 5-all. The set went to a tie breaker with Jones eventually converting on her seventh match point.
"I'm so thankful to get the win after being up in the second set. I had a comfortable forehand on match point and butchered it. The other match points she played really well," said Jones.
Jones now has to decide whether to take up the wildcard on offer for the ASB Classic.
"I don't play tennis professionally anymore and it's not something that has been on my radar for quite a while. So I would have to sit down and think about it, it's still a few weeks away so you would have to put in some good training. You don't want to go out and not be at your best, there's no point." Jones said.
