Mansfield (23), a graduate in marketing from the University of Otago, is the latest member of Brent Ward's sprint squad to make his mark on the national scene.
Over the past two years, he has won seven senior men's medals at national championships - two gold, three silver and two bronze.
Last season he was a key member of two gold-medal-winning relay teams.
His best individual performances were to win silver medals in both the 100m and 200m.
He has also won a bronze medal in the 200m.
His double target for this season is to qualify for the world championships in Berlin and the World Student Games in Serbia.
To do this he must lower both his sprint times from his current best times of 10.68sec (100m) and 21.19sec (200m).
His best chance is in the 200m where the qualifying standard is 20.79sec for the Student Games.
Mansfield showed good early-season form during the interclub athletics meeting at the Caledonian Ground on Saturday when he convincingly won the men's 200m in 22.06sec from training partner Andrew Moore (Hill City) who clocked 22.50sec.
Both times were legal because the wind reading was only 0.8m per second.
Mansfield put his foot down when entering the straight to move away from Moore and the other chasing runners.
"I'm happy about that," he said.
"I felt good over the last 50m and had lots of energy left.
"I was just blowing the cobwebs off."
But there were certain aspects of Mansfield's technique that will need work before he reaches peak form.
"I was leaning inwards too far around the bend," he said.
The sprints produced the best performances of the day, with Liz Wilson (Hill City) reducing her own Otago masters women's aged 46 to 50 Otago record to 13.77sec.
The old record of the pre-school teacher was 13.98sec.
She also won the women's masters 200m in 28.24sec.
Cory Innes (Taieri), who is chasing his fourth national senior men's 400m title this season, had too much strength over the final 30m when he won the 100m in 10.87sec from Andrew Moore (Hill City) who clocked 11.06sec.
The best of the younger sprinters was Toby Flett (Hill City), who won the men's aged 15 and 16 100m (11.30sec) and 200m (23.23sec) double.
Ten Southland athletes travelled from Invercargill to gain competitive experience before the national secondary schools championships to be held in Hamilton in December.
The best performed was Rebecca Gibson (18) who won the women's aged 17 to 19 200m in 25.98sec and was runner-up to Bethany Struthers (Taieri) in the 100m in 12.72sec.
Struthers was timed at 12.69sec.
Greer Alsop won the girls 14 and under 100m in 13.12sec and the triple jump with 10.19m.
The other strong Southland performances were in the 2km steeplechase won by Michael Sinclair in a personal-best 6min 29.14sec.
Christina Taylor won the women's event in 7min 30.24sec.
The other top Southland performances came from paralympian Jessica Hamill who won the AWD shot put with 6.18m.
Taieri athletes dominated the 400m hurdles, with Leslie Taylor winning the men's aged 17 to 19 race in 62.29sec and Biddy Skerten the women's aged 15 and 16 race in a personal-best 69sec.
The only legal throw by Jerram Huston (Taieri) of 12.64m was enough to win the men's shot put.
