The Australian said the reliability of the RB9 was especially pleasing, having racked up 101 laps - the most of any driver – on the second day at Jerez.
After two days of testing last year, Webber's RB8 was the fastest of the new cars, although he was delayed by three hours on the first day waiting for new parts.
Asked if he was happier with his progress in 2013, Webber said: "I think we are. It was very good day for the team in terms of how we worked and our preparation.
"It was important to make the most of the conditions and we did that - we've pretty much done our programme and got all the information we needed to.
"This morning's programme was ambitious but we pretty much nailed it. Our long runs, getting more confident with components on the car, went well too.
"In the end I was surprised with the amount of kilometres we did, it's quite good.
"We certainly learned a lot more than yesterday, and we'll learn more again tomorrow when Sebastian takes over.
"In terms of consistency I was very happy with the last few days and myself. The car gives me the confidence to push, and we can certainly build from there in terms of development."
AUTOSPORT special testing coverage:
Gallery Testing blog Technical blog Live commentary Trackside analysis