The FIA World Touring Car Championship was inaugurated in 2005. For one of the only three world championship series, along with Formula One World Championship and World Rally Championship, ADVAN has supplied the single spec tires since 2006 and was recently appointed as the sole tire supplier for the series until 2012 at the FIA World Motor Sport Council meeting. This was repeated acknowledgement for the performance of ADVAN racing tires by FIA and all participating drivers and teams as well.

This Portuguese round was an important event for the history of this championship because the second race at Porto (the 14th race of the series) was the 100th race of the championship's history which began at Monza, Italy, April 10, 2005. There was a celebration event on Saturday in the race weekend, together with an unveiling ceremony of the WTCC's 100th race commemorating plaque placed at Passeio da Fama in the city of Porto.

Despite such a celebratory atmosphere, the two races on the streets of Porto were really wild and saw a lot of accidents, being typical of the street track events.

Although the warm-up session on Sunday morning was hit by rain and run on the wet track, the sky was starting to clear up, as the time for start of Race 1 (the series' 13th race), 11:35 a.m., approached, just as if the sun wanted to celebrate this important event, and the surfaces were almost dry when all the cars were ready to start.

Led by Gabriele Tarquini, who secured the pole position in the qualifying session on Saturday, the rolling lap got underway. The Italian's SEAT Leon TDi was followed by a Chevrolet Cruze driven by Rob Huff who was the fastest driver in the warm-up session.

When green lights came on, the leading competitors rushed into Turn 1 and went through it without any mishap but there was a big accident on the pit straight further down the field. Starting from the ninth row, Jaap van Lagen of Lada and Sergio Hernandez made a heavy contact at the start and the Spaniard's BMW was pitched hard into the pit wall.

Hernandez injured one of his ankles in the accident and had to be taken to the hospital to receive medical treatment. Fortunately, his injury wasn't serious at all but it sidelined him from the second race of the day, the commemorative 100th of the series.

Then, at Turn 10 on the same opening lap, Augusto Farfus who started from seventh hit the back end of Alain Menu's Chevrolet, as the Brazilian made a mistake in the braking zone for the corner. Consequently, the Swiss' car was sent into the tire barrier and halted on the track sideways, so the car blocked almost half of the track width.

Tiago Monteiro in a SEAT Leon TDi and Nicola Larini in another Chevrolet Cruze were also involved in this incident as innocent victims and the race had to be stopped by the red flag because of these two accidents.

It took a long time to clear up the halted cars and debris and to repair the damaged barriers and the race finally restarted at a quarter past noon. After a rolling lap led by the Safety Car, the whole field started from their original grid positions. Starting again from the top slot, Tarquini made the most of the nature of the narrow street track in which overtaking is quite unlikely and scored his second win of the season, since the second race of Curitiba round in Brazil.

YOKOHAMA Independent Trophy was won by Stefano D'Aste driving the Wiechers-Sport's BMW 320si. It was his second victory in the class this year, after he took the first one in Valencia, Spain.

Race 2 started at ten to five p.m., after a longer than usual interval. On the 'reversed grid' formed by the top eight finishers of Race 1, Farfus sat on the pole position.

He was given a drive through penalty in Race 1 for causing Menu's crash but made up lost ground and finished the race in eighth. Given the advantage that rear-wheel-drive cars usually have at the standing start of Race 2, the penalty wasn't too shattering for him in retrospect indeed.

The current championship leader, Yvan Muller of SEAT Sport started from the sixth grid but immediately overtook his Portuguese teammate, Monteiro, and then moved up to fourth by a masterly move at Turn 2 to pass Larini.

On Lap 3, an interesting side-by-side battle between Larini and Tarquini suddenly ended at Turn 5 when they tangled with each other and hit the barrier. When the following pack came up to the corner, an independent SEAT driver, Mehdi Bennani, narrowly managed to avoid hitting their cars but he contacted with Tom Boardman as he came back to the normal racing line.

To deal with the double accident at the same corner, the Safety Car was called in. After the bizarre incident in the French round at Pau, the series organizer had appointed the dedicated safety car driver who is in charge throughout the season to prevent repeating another silly accident and this was his first event on duty.

After the race resumed, Rickard Rydell in second started to push the race leading Farfus so hard but their hotly fought battle was interrupted by another accident.

In the process of close racing, two independent class BMWs of Franz Engstler and Felix Porteiro contacted each other and both cars hit the guard rails on Lap 9. They were lucky enough to resume the race but Menu wasn't. The Swiss found his way was blocked by Engstler's car and had nothing to do but hitting it. As a result, he crashed heavily into the barrier and his halted car blocked the track again.

For the safety reason, the race was stopped by the red flag. The race restarted with just two laps remaining and Farfus maintained his lead position until the finish to become the winner of the championship's 100th race.

D'Aste scored a double win in the independent class and showed his persistence for the title contention.