Gold for Hoy as Pendleton takes silver in Melbourne
Olympic champion Hoy is aiming to rack up qualification points for London 2012
Chris Hoy won the men's keirin to clinch another gold at the track World Cup event in Melbourne
But Victoria Pendleton had to settle for silver in the women's sprint, behind Australia's Anna Meares.
Meares won the Commonwealth Games sprint in October, after Pendleton opted to miss the event.
On day two of competition - where vital qualification points for the 2012 Olympics can be gained - Ed Clancy took bronze for Britain in the men's omnium.
Scotland's four-time Olympic champion Hoy - who was beaten in the opening knockout round of the men's sprint at last month's European Championships - left nothing to chance by winning his heat and second round races to progress to the final unbeaten.
The 34-year-old then claimed victory ahead of Teun Mulder of Holland and France's Mickael Bourgain in the final.
"The results have reflected my training performance over the last few weeks, but it's not until you actually get to race day when you're able to show if you can produce the goods in competition."
In the women's sprint, the British duo of Pendleton and Varnish were paired together in the best-of-three quarter-finals as Pendleton saw off the challenge of her team-mate 2-1 after losing the opening race.
She then progressed through the semi-final when Olympic bronze medallist Guo Shuang of China crashed, setting up a final meeting with Olympic silver-medallist Meares.
Commonwealth champion Meares won the first two races, meaning there was no need for a decider as Pendleton had to settle for the runner-up spot.
Britain's Olympic champion has been racing with a back problem sustained in training.
But she said: "I am pleased with my form, you can't be fast all the time and you have to make choices about racing.
"Anna is probably the most experienced rider on the scene. She's still here at the top of her game."
World champion Clancy was second entering the second day of the six-event omnium competition and finished third in the individual pursuit, the fourth event.
A 12th-placed finish in the scratch race was followed by first place in the time trial, which promoted him into third overall as New Zealand's Shane Archbold triumphed.
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