Molinari drove the green at the 306 yard third and two-putted for his seventh birdie, then hit his tee shot to four feet on the next.
He added yet another on eight under - that made it an incredible 17 under for his last 30 competitive holes - but Donald was only two back as he kicked off the front nine with three successive birdies to make it five in six holes, while Kjeldsen was one further back.
Molinari improved to ten under on the long fifth and suddenly was four clear of the field, with Donald bogeying the 452 yard fifth when a chip failed to make it up a bank left of the green.
There were three holes left for the Italian and if he could birdie them all it would be The European Tour's first 59.
England's Andrew Johnston had a moment to remember, holing in one with an eight iron at the 167 yard 11th and leaping to two under as a result.
The chance of making history went when Molinari could "only" par the seventh and eighth and his lead was reduced to three when Kjeldsen birdied the 12th and 14th to reach seven under, one ahead of Donald.
Els fell eight back when he needed three attempts to get out of a greenside bunker at the long sixth and ran up a seven, his second double bogey of the day.
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