Patience (17), a pupil at Otago Boys High School, was sixth in the 1500m and eighth in the 800m freestyle in Monterrey in his first world championships.
Both events were swum as timed finals and Patience gained personal best times in both events.
The fastest ranked swimmers before the championships swam in the faster evening sessions and Patience swam in the morning heats because his qualifying times were slower.
The World Youth Championships brings together the best aged 18 and under swimmers in the world, with all of the major swimming nations represented.
Patience swam in the morning and recorded a time of 8min 13.86sec, a personal best time by 4.79sec, and then had to wait for the final in the evening to see whether he made top eight.
The following day, Patience swam in the New Zealand 4 x 200m freestyle relay team that just missed the final when it placed ninth in the heats.
Patience's 1min 54.06sec split for the 100m showed that he was holding his form.
In the 1500m freestyle, Patience was not in the fastest heat, so it was another morning swim.
He was ranked 14th going into the event with a time of 15min 45.35sec and was in lane eight in the fastest morning heat with countryman Kane Radford.
Patience had another outstanding swim to win the heat in a time of 15min 38.19sec - a personal best time by 7.16sec - and had another long wait to see if he could tip a couple out of the final and place in the top eight.
He had a final placing of sixth and was less than 1.4sec behind the fourth-placed swimmer.
Patience had two swims that gained him 850 Fina points, two strong personal best times and two top eight placings.
Patience had been beaten by Radford in the 1500m at the New Zealand open championships last March and at the Oceania championships.
He reversed the positions at the world championships, with Radford finishing 9sec behind Patience in 11th place.
The highlight of the winter meets at Moana Pool this month was a swim from 11-year-old Phillip Baxter (Waves), who reduced his own 200m breaststroke record by 4sec with a time of 3min 06.45sec.
This was the 1995 record he took off Sam Caradus at the Neptune Carnival in early June.
Adam Simpson (Waves) continued his good form with personal best times in the 100m backstroke and 100m freestyle.
His time for the freestyle was significant because he swam under 2min for the first time when recording 1min 59.75sec.
Rhys Pryde-Wall (Waves) swam three personal best times, with the most notable being a fast 25.85sec in the 50m freestyle, which reduced his personal best by 1.08sec.
