Jacques Villeneuve said Sebastian Vettel's tyre blow out at the Belgian Grand Prix gave Formula One some much-needed unpredictability.

Vettel was on track to finish third at Spa-Francorchamps on Sunday before his right rear tyre failed on the penultimate lap.

The German went on to finish 12th and he was furious with tyre manufacturer Pirelli, claiming "if that happens 200 metres earlier, I am not standing here right now".

But ex-F1 driver Villeneuve argued the sport could do with more reliability problems late in races.

"With Vettel blowing his tyre two laps from the end, that was the big shocker," the Canadian told Omnisport.

"That was what we used to get 20 years ago, cars breaking down with two laps to go, or a tyre or an engine, and you don't get that anymore. So 10 laps to go everyone kind of knows what's going to happen and in that race there was a big surprise.

"Obviously it was not good for Vettel, it's not good for the Ferrari fans and it was little bit risky but it created an unknown and that's always good for the sport in a way because it creates entertainment."

The Belgian GP continued Williams' trend of missing out on the podium in 2015, with Felipe Massa finishing sixth and Valtteri Bottas claiming ninth.

While Williams still sit third in the constructors' championship - matching their result from 2014 - their two drivers have only managed a solitary third-place finish each this year.

Last year, Bottas and Massa combined for 10 podium finishes and Villeneuve said he feels something is wrong with Williams' engine.

"There is something not working on the Williams car because they're really lacking top speed for a Mercedes engine, which was a very strong point for them last year," he said.

"So there's something that is not working. Monza [the Italian GP venue] is very different because there's not a lot of corners; so maybe they can adapt their set-up a little bit."