Jose Maria Lopez has dedicated his second consecutive WTCC title to his family, who he admits made great sacrifices so that he could achieve his success.

The Argentine ensured back-to-back crowns by claiming pole position and victory in race one at the Chang International Circuit in Thailand, before going on to take fourth place behind Citroen team-mates S?bastien Loeb and Ma Qing Hua in the day's second race.

The Citro?n C-Elys?e WTCCs had started the day in style by achieving the unprecedented feat of occupying the top five places in qualifying but it was Lopez quickest of all, setting himself up for his title shot ahead of Loeb, Yvan Muller, Hua and Mehdi Bennani.

With the main stand packed as the cars lined up on the starting grid, the defending champion got off to a perfect start and reached the first turn in the lead. Although the race was interrupted by the safety car as Muller's damaged Citroen was cleared away, there would be no change for the lead before the finish and, despite coming under constant pressure from Loeb, L?pez clinched both his ninth race win of the season and the points he needed to secure a second title.

"I am so happy to have won this second title," Lopez admitted, "Last year, people focused on the fact that mine was the first title for an Argentine driver since Juan Manuel Fangio but, this year, I'm thinking first and foremost about my family, who have sacrificed a lot for me to be able to come and race in Europe.

"I started my career at the age of 23 and, after all these seasons, my passion remains undiminished. Retaining this world championship title is a massive achievement, and I would like to thank the Citro?n Racing team, who gave me a chance and have given me carte blanche to compete hard against my prestigious team-mates. I think the standard has gone up a level this year. That is probably why I'm feeling even more emotional than I did in 2014. I want to savour this moment."

The celebrations would have to wait, however, as the drivers were immediately back out on track for race two. With Muller again falling by the wayside at the very first turn, the race was full of incident, with plenty of overtaking. While Loeb and Hua gave chase to Honda's Tiago Monteiro - a pursuit ultimately foiled by a red flag - L?pez came home fourth to pad his points total for the season.

"After winning the manufacturers' championship in Shanghai, it is a great joy to see Jos? Mar?a L?pez claim another drivers' title," Citroen team principal Yves Matton said, "It is just reward for a season of consistently excellent performances."