Spain's domination of the first half of the Dakar Rally continued apace on Tuesday as both former world rally champion Carlos Sainz and Marc Coma won the fourth stage of the car and motorbike disciplines respectively. Their victories helped them extend the overall lead in both categories. Sainz won his second stage of this edition in beating closest rival Qatar's Nasser Al-Attiyah, winner of the two other stages, by six seconds to extend his lead over him to 3minutes 46seconds. France's 2006 champion Luc Alphand, who lost a lot of time on Monday, was third in the stage over two minutes behind. Coma had earlier strengthened his grip on the motorcycling section after winning the 459km special from Jacobacci. Coma added to his opening and third stage wins in seeing off Frenchman Cyril Despres - who has virtually given up all hope of winning a third Dakar after losing over an hour in the first three stages - by 1min 17sec and American Jonah Street by 1min 21sec. Street's showing was enough to take him second overall over 40 minutes off the pace. David Fretigne of France, fourth on the day, stands third overall. Coma admitted that the stage had taken a lot out of him after recording his third stage victory of the race. “This (the stage) was more physically challenging because I started to feel the efforts of the first few days,” said Coma. “Today (Tuesday), was shorter but really harder than the previous stages.” Earlier, two British competitors in the cars section were placed in an artificial coma in the central town of Santa Rosa after an accident during Saturday's first stage, organizers said. Suffering from pulmonary problems, Paul Green and co-driver Matthew Harrison were taken to hospital in Santa Rosa and placed in an artificial coma in a bid to speed up their recovery. Organizers said it was expected they would be brought out of the coma on Thursday.