However, the world champion, Tommi Makinen, is more than 13 minutes adrift while team-mate Freddy Loix was lucky to escape serious injury after a crash as Mitsubishi's hopes of a record seventh successive rally victory faltered.
Loix was airlifted to Nairobi hospital after he hit a ditch at 100mph, but escaped with a sore neck after his car ended up upside down on the road.
"He is going to be fine," said the rally's chief medical officer, Dr Sudhir Vinayak. "There are no major injuries."
Loix will stay in hospital overnight as a precautionary measure while co-driver Sven Smeets escaped without injury from the crash on the third stage yesterday.
Burns showed why he was being tipped pre-season as a title favourite with an expert display in the Subaru, having claimed his maiden victory on the Safari 12 months ago in a Mitsubishi. The 28-year-old from Oxford, who has just two championship points from the opening two rallies, took over at the top of the leaderboard on the first stage.
Sainz responded on the next section, but, then on the road to Timbuktu, Burns cut the deficit to less than seven seconds with another fastest time. Burns, who rejoins Subaru as replacement for McRae, then eclipsed Sainz by 53 seconds on the last and longest stage of the day - around 70 miles - to regain the lead. McRae is less than two minutes behind with two days left despite smacking into a rock in his Ford Focus on the dusty, potholed roads south of the capital. "I can't believe that we're still going, because the impact was so large," said McRae, searching for his first points of the campaign. "The Focus must be built like a tank if it can survive that."
McRae's team managed to repair the car at a service halt and the Scot responded with the second fastest time on the final stage to be well in contention for a podium finish.
Makinen was fastest on the last timed section, but is more than 13 minutes adrift and facing a huge task to complete a third victory in succession, which would extend his 13-point lead in the championship.
Finland's triple world champion hit problems on the opening stage when simultaneous punctures to his rear tyres left him stranded for over 10 minutes.Reuse content