Petria Thomas set a new Commonwealth record and won her fourth gold of the Telstra National Short Course Championships with a sizzling swim in the women's 100m butterfly in 56.93 on the final night of competition at the Melbourne Sports and Aquatic Centre.

Her time was 0.80 under her own Commonwealth record and just 0.38 secs outside Martina Moravcova's world record of 56.55, set at ths year's World Cup in Berlin.

Thomas led by half a body length over the first half of the race to eventually pull away and win by nearly two body lengths from the rest of the field. "I've been swimming well, and I knew if I could control it I'd swim a good time," she said, adding she had gained much confidence from Manchester and Yokohama.

"The two relay wins at the Pan Pacs were a highlight for me," said Thomas, who has swum a stunning 37 races in the last two months. "It was a great feeling, beating the Americans for the first time."

Silver went to fellow Telstra Dolphin Felicity Galvez in 59.17, and bronze to Campbelltown's Lara Davenport in 1.00.00.

Thomas backed up later in the night, winning silver in the women's 200m freestyle behind Manly's Elka Graham.

Graham, Commonwealth Games gold medallist and long course national title holder, led from the start to defend her title, touching in 1.55.93.

"I'm so stoked, I really wanted to go under 1.56.90," said Graham afterwards. "Yesterday it was exactly 24 months until the Olympics, so I'll enjoy my break and go from there, see what happens."

Silver went to fellow Telstra Dolphin Petria Thomas in 1.57.00, and bronze to Sydney University's Kirsten Thomson in 1.57.31. The trio were members of Australia's silver medal winning 4 x 200m freestyle relay team at the Sydney Olympics.

Michael Klim completed a successful comeback with gold in the men's 100m freestyle in a speedy 48.22, his second gold in just his second race back from injury.

After the race Klim said he still had much work to do. "I'm very rusty with my racing so it's good to get in and have a race," he said. "But there's a long way to go."

Klim has won the 100-200m freestyle double at these championships, but has not contested the butterfly events despite holding the 100m fly world record. Asked whether he would contest the fly again, Klim nodded. "Definitely. Being the world record holder there's a bit of a legacy there."

Silver went to City of Perth's Antony Matkovich in 49.06, and bronze to Nunawading's Andrew Dyson in 49.14.

Commonwealth and Pan Pac gold medallist Alice Mills swam strongly to take gold in the women's 200m IM, controlling the race from the start to take her first national title in 2.12.49.

A breakthrough performer for the Telstra Dolphins and the baby of the team, Mills was delighted with the win. I'm just so happy I've won that race. It's my first individual title," she said.

Mills took a half body length lead in the butterfly and breaststroke legs before being challenged by fellow Telstra Dolphin Jessica Abbot in the breaststroke, turning together in to the final freestyle leg. Mills then pulled away, leaving Abbot to collect silver in 2.13.63.

Bronze went to Pan Pac 400IM champion Jennifer Reilly in 2.14.38. In the men's 200m breaststroke Commonwealth champion and member of last night's world record breaking "Deadly medley" Australian relay team Jim Piper came away with the gold in a time of 2.09.22.

Piper fought a close race with Brothers' Brenton Rickard over the first half of the race, maintaining a narrow lead until pulling away over the last 50m to win by half a body length.

"That last 50m I was thinking 'Oh, the break's soon, the break's soon'," said Piper after the race. "I'm happy with the win and happy with the time. After the break I'm looking forward to getting back into hard training."

Rickard took the silver in 2.10.49, and bronze went to a fast finishing Luke Trickett of Willoughby in 2.11.79.

Olympic silver medallist Leisel Jones stormed home in the final 25m of the women's 100m breaststroke to win gold in 1.06.64 by three one-hundredths of a second from Commonwealth Games silver medallist Brooke Hanson, who touched in 1.06.67.

Hanson, winner of the 50m and 200m breaststroke at this meet, led for most of the race with Jones close on her heels, before Jones came home on the last lap.

"I just tried to work the last 25m, and keep my stroke long," said Jones.

The bronze medal went to Olympian Tarnee White in 1.07.40.

Matt Welsh, twice a world record breaker at this meet, collected his third gold in the men's 200m backstroke in 51.27, just outside the Commonwealth record of 50.95 he set as part of last night's world record breaking "Deadly medley" Australian relay team.

The win capped off a tremendous week for Welsh, who said he was very much enjoying being back home in Melbourne after campaigns in Manchester and Yokohama.

"I'm absolutely going to be at the World Cup meet here in December. I'm really looking forward to that," he said after the race.

The silver medal was won by Victoria Park's Matthew Spicer in 53.96, and the bronze by Telstra Dolphin Ethan Rolff in 54.26.

In the women's 200m backstroke Telstra Dolphin Kelly Tucker went neck and neck with Norwood's Karina Leane for the first half of the race, before pulling away to take gold in 2.08.19, a new personal best time.

Fellow Telstra Dolphin Melissa Morgan of Burnside stormed home to snatch the silver in 2.08.70, with Leane taking the bronze in 2.09.56.

Olympian Robert Van Der Zant swam a strong back half of the men's 200 IM to win gold in 1.58.05 from West Coast's Adam Lucas, who touched in 2.00.05.

Lucas led out in the backstroke and butterfly legs before Van Der Zant caught up in the breaststroke leg and pulled away in the freestyle to win by half a body length. "I really tried to work the second half of the race," said Van Der Zant.

Bronze went to CJ Aquajet's Ashley Anderson in 2.01.15.

Geoff Huegill took gold in the men's 50m butterfly, an event in which he is the current world record holder, storming home to touch in 23.37 to back up after last night's effort as part of the world record breaking 4 x 100m IM Australian team.

Fellow Telstra Dolphin Adam Pine won the silver with a time of 23.96, and bronze went to City of Perth's Robert Sharp in 24.60.

Miami's Stephen Penfold won his second gold of the meet in the 1500m freestyle, winning in a new personal best time of 14.41.84.

Penfold was well ahead and swimming on his own for most of the race, and his time makes him the fourth fastest Australian ever behind only training partner Grant Hackett, Kieren Perkins and Daniel Kowalski. "To be fourth behind names like that, it's excellent," Penfold said. "I haven't done a 1500m in a year and half due to injury, so it's just fantastic."

The silver medal went to The Hills' Grant Cleland in 15.09.17, and the bronze to City of Perth's Travis Nederpelt in 15.12.19.

The women's 4 x 100m medley relay went down to the wire with Redcliffe Leagues Lawnton A duelling it out with Carey Aquatic, Redcliffe Leagues Lawnton A pulling away over the final metres to take gold in 4.04.13.

Carey Aquatic collected the silver in 4.05.08, and Chandler took the bronze in 4.11.44.

In the men's 4 x 100m medley relay, Matt Welsh gave Melbourne Vicentre a lead of two body lengths, but the team was overtaken in the butterfly leg by Adam Pine of Yeronga Park, who went on to win in 3.36.13.

Antony Matkovich of City of Perth brought his team home for silver in 3.41.53, the Melbourne Vicentre team holding on for the bronze in 3.41.55.