Colin McRae's Dakar Rally hopes were hit on Wednesday when he got stuck in a dune on the race's longest stage.
Masuoka dominated the day
The Scot eventually finished more than 25 minutes behind Hiroshi Masuoka, who almost doubled his lead after taking victory in the 701km seventh stage.
Masuoka is now 11 minutes and 42 seconds ahead of team-mate Stephane Peterhansel with McRae in third more than 40 minutes in arrears.
Cyril Despres took the overall lead in the 17-day race's motorcycle category.
Masuoka finished the stage, between Tan Tan in Morocco and Atar in Mauritania, in a time of five hours 58 minutes and 35 seconds.
He had a worrying incident on the way when just after the rally crossed into Mauritania, competitors were
held up by soldiers who asked for money to allow them to
pass through the country.
"A soldier pointed a gun at me," said Masuoka.
"He said 'stop and give me some money'. But I didn't give him
anything and I took back my passport.
"It's the first time it's happened to me and I hope it will be
The rally's sporting director Patrick Zaniroli said: "It's not a
customs problem, it's a local power struggle that is tarnishing the
image of Mauritania."
McRae came home in fifth but lost valuable time after hitting trouble 456km into the day across the Oumaghawaba Erg.
"It was going really well. Peterhansel passed us and we just
sat behind him, which was great, but then we lost 20 minutes
stuck in the sand," said the Scot, who also suffered two
The Scot's fellow former World Rally champion Miki Biasion is out of contention after failing to take the start line in the morning due to mechanical trouble.
The motorcycle places were turned on their head after overnight leader Isidre Esteve Pujol suffered a heavy fall.
The Spaniard went down after the first checkpoint and dropped out of the top 10 as a result.
France's Richard Sainct, the reigning champion and a
three-time Dakar winner, won the stage despite struggling with an arm injury.
Despres came home in third, a result that saw him climb to the top of the standings three minutes ahead of Nani Roma.
Thursday's 393-km eighth stage is from Atar to Tidjikja.
Overall positions after stage seven:
1. Hiroshi Masuoka (Jpn) Mitsubishi)
at 13 hours 40 minutes 58
2. Stephane Peterhansel (Fra) Mitsubishi +11mins 42secs
3. Colin McRae (Gbr) Nissan +41:29
4. Gregoire De Mevius (Bel) BMW +43:59
5. Jean-Louis Schlesser (Fra) Schlesser Ford +48:04
1. Cyril Despres (Fra) KTM
at 15 hours 23 minutes 30 seconds
2. Nani Roma (Spa) KTM +3mins 3secs
3. Richard Sainct (Fra) KTM +3:21
4. Alfie Cox (Rsa) KTM +5:01
5. Jean Brucy (Fra) KTM +7:07