‘‘Dual World Champion ... I cannot believe it ... is this even real??#?speechless?’’ wrote the 18-year-old from Devonport after capping a successful five days of racing for Australia at the UCI Junior Track World Championships in Korea.

Stewart’s nail-biting countback victory in the omnium saw Australia top the medal tally with a total of 13 including five gold, three silver and five bronze.

‘‘It feels incredible, I did not expect it at all, but I just didn’t give up and some good luck finally came my way! I’m still in disbelief,’’ said Stewart who who had teamed up with Launceston’s Lauren Perry plus Alex Manly, Dani McKinnirey and Josie Talbot to win the team pursuit on day 1.

The two-day omnium began with Stewart placing sixth in the scratch race before winning the individual pursuit in 2mins 26.903secs to move up to second place on 70 points, six off the lead.

In the elimination race, Stewart was the fourth last rider to be eliminated and ended day 1 in third position on 106, 10 points in arrears of Amalie Dideriksen (DEN).

Stewart posted the fourth fastest time of 37.156 in the 500m time trial to sit fourth overall with Italian Martina Alzini proving the fastest in 36.711.

After posting the second fastest time of 20.101 in the flying lap round, Stewart moved back into the medal positions as round winner Alzini moved into the lead.

A five-rider crash early in the points race involving leader Alzini and second-place Dideriksen caused a temporary halt. Alzini was quickly able to return, but injuries forced Dideriksen to retire from the event, with Stewart able to reduce her gap to four points with two sprints remaining.

She picked up two more points in the penultimate sprint to leave her with a two-point deficit ahead of the finish. After hitting out early she held on for third and two points, leaving scores tied with Stewart collecting gold on a countback.

‘‘That points race was easily the most hectic race I have ever ridden!’’ she said.

‘‘I had no idea I had won until rolling a couple of laps and seeing Belinda [Goss] and Clay’s [Worthington] faces and them holding up one finger,’’ said Stewart, who now heads to Europe to prepare for the road world championships in September.

‘‘So much happened in the race, I really didn’t know where I was sitting on the scoreboard, I just had to listen to Belinda yelling where I needed finish in each sprint!

‘‘I’m extremely pleased with both my efforts as well as the whole team! Australia finished on top of the medal tally once again, and that comes down to how hard each and every member worked coming into the championships.

‘‘So proud to be a part of such a professional organisation in Cycling Australia and being lucky enough to work with great coaches and support staff.’’

Alzini claimed silver and Soline Lamboley (FRA) bronze.

It has been a stellar 2014 for Australian track cycling, with the nation topping the medal tally at February’s world championships in Colombia, April’s para-cycling world championships in Mexico, the Commonwealth Games in Glasgow and the junior world championships in Korea.