"I guess it's some momentum we can take into the test series," Southee said. "To get another six overs under your belt in the middle is good practice going into the test.
"There are still a few days until that first test match so, hopefully, the weather holds off and we can carry on as a bowling unit from where we have left off in this game."
The bowling unit will be bolstered by Chris Martin, Doug Bracewell and Neil Wagner, along with spinners Jeetan Patel and Todd Astle. They can't all fit into the first test lineup and it's possible new Zealand will carry the same attack into the match that played the last test against India in August.
Southee and Bracewell were joined by the ever-improving left-armer Trent Boult and Patel, with James Franklin providing backup.
They will have a difficult challenge on their hands against a powerful Sri Lankan batting lineup that includes the likes of Mahela Jayawardene, Kumar Sangakkara, Tillakaratne Dilshan and Thilan Samaraweera but Southee thinks they have the potential to put the home side under pressure and set things up for their own batsmen.
"There are a lot of runs scored between their top five or six batsmen so it's going to to be a big ask with a fairly inexperienced bowling lineup, but we've all shown we can perform at test level," he said.
"It's a good challenge to play against some world-class batsmen on some flat wickets in their own conditions, so it will be a big test for the bowlers but I'm sure everyone is excited.
"If you weigh up their batsmen and bowlers, they're a strong batting side, and if we can do our job as bowlers and set the game up for the batsmen then there's no reason why we can't turn this tour around and have a good finish with the test matches."
It has been some time since New Zealand won a test. They won the year's opening match against Zimbabwe in Napier in January by an innings, but have since been beaten by South Africa (1-0), the West Indies (2-0) and India (2-0).
In fact, 2012 has been lean overall. Since the Zimbabwe tour, they have played 31 matches in all forms of the game and won just four, lost 21, tied two (which were lost in super overs), drawn two and experienced two no-results.
It's a dreadful record, and one New Zealand could struggle to turn around this summer with a tour of South Africa and home series against England.
Incredibly, the weather forecast for Galle is for five largely fine days. Many of the players in both sides won't know what has hit them.