New Zealand has had lopsided 10-wicket victories over Kenya and Zimbabwe, but lost to three-time defending champion Australia by seven wickets.
"We've had two convincing wins but obviously you can't dwell on the loss to Australia," Southee said. "It's a tournament where you can't dwell on things too much - you've got to move on."
The right-arm paceman, who has taken 59 wickets in 46 ODIs, grabbed three wickets in each of the wins over Kenya and Zimbabwe, but only one against the Australians.
"It's a chance to put the wrongs we did against Australia and turn them into rights," Southee said as he looked ahead to New Zealand's second match against a test-ranked nation at the tournament.
Southee believed the recent 3-2 ODI series loss to Pakistan was "closely contested", and said his team will take confidence out of the last game at Eden Park, which New Zealand won.
The Kiwis had experienced in recent months how tough the conditions are for the fast bowlers on the slow subcontinent wickets after failing to win a match in series against India and Bangladesh.
But Southee still saw positives from those two disappointing results.
"We're lucky a majority of the side came over and we played a lot of cricket on the subcontinent," he said. "Although the results didn't go our way ... we've managed to learn from those poor experiences."
Pakistan is unbeaten in three matches so far against Kenya, Sri Lanka and Canada, with Misbah-ul-Haq carrying his fine form from New Zealand.
Misbah, who scored 203 runs at an average of 67.66 in the New Zealand series, has scores of 63, 83 and 37 in the three World Cup matches.
Southee hoped his bowlers would come good against the 35-year-old middle-order batsman, who is playing in his first World Cup.
"He's in a rich vein of form," Southee said. "Hopefully we've learnt from the way we bowled against him in New Zealand and we can work on a couple of things to try and put an end to the form he is in.
"He's playing exceptionally well along with the likes of (Shahid) Afridi and they have a couple of guys who are standing up in key moments in games."
