THIRD ROUND LEADERBOARD:
-12 C Schwartzel (SA), E Els (SA) -11 P Harrington (Ire)-10 R Allenby (Aus)-9 B Haas (US) -8 M Kaymer (Ger) -7 M Kuchar (US), P Casey (Eng), V Singh (Fiji), S Hansen (Den) Selected others: -4 P Mickelson (US), G McDowell (NI) -2 L Donald (Eng) -1 R Fisher (Eng) level L Westwood (Eng) +1 R McGowan (Eng), S Garcia (Spa) +2 S Dyson (Eng) +6 R McIlroy (NI), I Poulter (Eng) +13 O Wilson (Eng)
Els shot a two-under 70 in Florida
South Africans Ernie Els and Charl Schwartzel were tied for the lead at 12 under after the third round of the WGC-CA Championship at Doral, Florida.
Overnight leader Els wasted some good birdie chances to finish with a 70, while Schwartzel fired a five-under 67.
Ireland's Padraig Harrington bogeyed the final hole for a 67 to lie second on 11 under at the Blue Monster course.
Australian Robert Allenby was third on 10 under, with England's Paul Casey a further three shots back after a 68.
The 25-year-old Schwartzel, who won two weeks in a row at home in South Africa in January, stayed with the 40-year-old Els last week and was part of the group helped out by the former Open champion's Foundation as he grew up.
"I think it's a wonderful cool story," said three-time major winner Els, who will play with his countryman in the final pair on Sunday.
"We talked about it, but I don't think in our wildest dreams we would have imagined it. It's great for South African golf and world golf - he's a new young star and a force to be reckoned with.
"He owes me big time! I fed him well and gave him good wine. He almost feels like a little brother in some ways.
"We will shake hands and then play 18 holes as hard as we can."
Dubliner Harrington made six birdies - the last of those on the 17th after a stunning 379-yard downwind drive - on his way up the leaderboard.
But a bogey five on the par-four 18th spoiled his run as he chases a first title since he won the US PGA - his third major - in 2008.
"That finish leaves a sour taste, but it has no effect on the outcome tomorrow," said Harrington. "Who plays the best is going to win.
"I putted all right today and I hit a good second putt. What can you do? I will take certainly take another 67."
German Martin Kaymer shot the day's top round with a six-under 66 moving him into sixth place on eight under, one shot ahead of Casey, Fijian Vijay Singh (70), Dane Soren Hansen (71) and American Matt Kuchar (67).
World number six Casey, who could go second in the rankings with victory at Doral, was given extra motivation afterwards when told about television commentator Johnny Miller calling him "the biggest under-achiever in golf."
"I feel I'm coming into the prime of my career," said the Englishman, who has been second and fourth in his last two events and won three times last season before tearing a rib muscle.
"I've gone through ups and downs and I'm just coming off an injury."
Asked specifically about Miller's words he added: "I can't comment on that.
"There's a lot I could say, but I will leave you to defend me. It's a back-handed compliment, I suppose."
American Phil Mickelson, the world number three and defending champion, hit five birdies and five bogeys in his level-par round to end four under.
Northern Irishman Graeme McDowell did his hopes of staying in the world's top 50 - and thereby earning a place in the Arnold Palmer Invitational in two weeks' time - no harm with a two-under 70 to also finish four under.
England's Luke Donald shot 69 for two under, Ross Fisher got round in 70 for one under, while Lee Westwood had a 74 to end level par.
Ross McGowan (70) was another stroke back, Simon Dyson (73) was two over, while World Match Play champion Ian Poulter (72) remained six over alongside Northern Ireland's Rory McIlroy (73).
Oliver Wilson's poor week continued as he shot a 77 to prop up the field on 13 over.