The Finn was second in both 90-minute sessions at the steamy Sepang circuit behind Lewis Hamilton and then Nico Rosberg to give him hope of being more competitive in Sunday's race after a disappointing start in Melbourne a fortnight ago.
The 2007 world champion was hit on the first corner in Australia by Kamui Kobayashi's Caterham en route to finishing seventh, almost a minute behind race winner Rosberg.
"This was definitely a positive day and I had a better feeling compared to Friday in Melbourne," the Finn told reporters.
"I was more comfortable with the F14 today and even if we had no problems whatsoever, we know there's still a long way to go and a lot to do.
"Our programme concentrated on car set-up and on testing the compounds that Pirelli has brought here. The handling seemed to be good."
Raikkonen had dismissed suggestions that his struggles at the Albert Park race were caused by a braking issue.
He said instead that the car would need to be personalised to his liking if he was going to match the successes of his first three-year spell with the Italian team which ended in 2009.
Alonso was 11th fastest before improving to fifth in the second session, 0.194 seconds behind Rosberg.
The Spaniard was more guarded when talking about possibly improving on his fourth-place finish in Melbourne.
"We are on a learning curve, which is not unusual for the start of a championship and, to find out how competitive we are, as usual we will have to wait until Saturday and Sunday," the double world champion said.
"Usually, Friday is a very confusing day, because everyone is working on their own programmes, but this year it's even more the case because of all the new elements.
"Everything went well, with no reliability problems and we managed to do a fair number of laps, enough to get a good understanding of the tyres, which will be a very important factor here because of the high temperatures."
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- Motor Racing
- Nico Rosberg
- Lewis Hamilton
- Kamui Kobayashi
- Sebastian Vettel