Rob Huff recorded the quickest time of the two World Touring Car Championship free practice sessions at Porto, more than a second quicker than his nearest rival.
Alain Menu led the way in the first session as Chevrolet dominated proceedings once again, with their trio of drivers filling the top three places. Huff had been top for much of the session but he would be demoted to third by his teammates at the end of the session. Muller was just 0.088 seconds shy of Menu, with Huff only a further five thousandths of a second adrift.
Tom Coronel was the best of the rest, six tenths off in his ROAL BMW. Local man Tiago Monteiro was fifth for SUNRED, one place ahead of teammate Fredy Barth. Stefano D'Aste continued to show great pace upon his return in seventh, just ahead of Norbert Michelisz.
Gabriele Tarquini was ninth with no repeat of the technical gremlins that hampered him in Friday testing, just ahead of teammate Pepe Oriola.
In the second session Huff lowered the lap record for the renovated circuit further by clocking a time that was 1.047s quicker than Muller. With Menu only able to post the 11th fastest time Tarquini assumed the third fastest time, ahead of Coronel and Tarquini.
Franz Engstler was the leading Yokohama Trophy runner in sixth, just ahead of his team's other driver Kristian Poulsen. Michel Nykjaer was next up in eighth, with Michelisz and Darryl O'Young rounding out the top ten.