Willing opposition came from United's youth team, which also faces a tough challenge against Auckland at Tahuna Park at 1pm tomorrow.
Coach Mike Fridge described the midweek game as ''good value''.
He was concerned that fringe players, and those returning after injury, were not getting the competitive games needed to bring them up to speed and maintain the sharpness required for national league competition.
Certainly, the spectators who turned up at Tahuna Park on Wednesday evening were treated to an intense game in which no quarter was asked.
A good blend of skill and physical aggression tested players on both sides, and also involved referee Hamish Phillip's experienced match control.
Initially a bit overawed by the seniors, coach Kevin Scoullar's youth side rose to the challenge, and both sides showed their ability to keep steady possession and yet look to launch early attacks that tested the squad's goalkeepers.
The final score was 3-2 to the senior side, and both coaches would have gleaned information to use in selecting sides for this weekend's matches.
Wellington, coached by Matt Calcott, is second-top and the only unbeaten side left in the ASB Premiership.
In last week's impressive 4-0 win over Auckland City, goals came from Michael Gwyther (20th and 62nd), Luis Corrales (60th) and Jarrod Smith (74th).
However, Auckland was reduced to 10 men on the hour mark, and the league leader may also have had one eye on this week's Fifa Club World Cup campaign in Morocco.
Southern United is in fifth place, five points behind Wellington but with a game in hand, so a win tomorrow could hoist Fridge's team back into contention for a top-four playoff spot.
A few regular first-team players sat out the midweek game. Victor Da Costa, Eder Franchini, keeper Tom Batty and Craig Ferguson, possibly with niggling injuries, sat and watched, but all are expected to be available for the Wellington game.
Defender Matt Joy looks unlikely to play again for some time, after having had surgery.
Clearly, Fridge will be looking for more accurate finishing than was displayed in Invercargill last week, where Southern should have been several goals ahead in the first quarter against the Phoenix reserves.
''If we can continue to create chances as we did down South, then it boils down to getting shots on target, and we have been working hard on that aspect of the game,'' Fridge said.
''Wellington is obviously on a high after beating Auckland but if we hit our best form, we can maybe cause an upset.''
Scoullar echoed Fridge's sentiments ahead of the youth side's game against Auckland.
''We have home advantage at Tahuna, and while Auckland United is below us on the table, we will not be taking this match lightly, and want all three points to move up the table,'' Scoullar said.
Southern youth's remaining fixtures are against Waitakere (away on December 14) and Canterbury (December 21).
