SECOND ROUND LEADERBOARD:
-10 E Els (SA) -9 R Allenby (Aus)-7 B Haas (US), C Schwartzel (SA)-6 S Hansen (Den), P Harrington (Ire) Selected others: -4 P Mickelson (US) -3 P Casey (Eng) -2 L Westwood (Eng) level R Fisher (Eng), G McDowell (NI) +1 L Donald (Eng), S Dyson (Eng) +3 R McGowan (Eng)+5 R McIlroy (NI)+6 I Poulter (Eng) +8 O Wilson (Eng)
Els won a PGA event round the Doral course in 2002
Ernie Els shot a bogey-free 66 to take a one-shot lead at 10 under after the second round of the CA Championship.
The South African strung together a run of three successive birdies from the 14th as nearest rival Robert Allenby faltered in Miami.
American Bill Haas matched Els's 66 to end three shots off the pace alongside first-round leader Charl Schwartzel.
Ireland's Padraig Harrington moved into joint-fifth with a 68, but England's Paul Casey fell back with a par round.
World number six Casey had taken a share of fifth place overnight with an opening-round 69, but found himself two over for his second round through 11.
Birdies on 16 and 18 helped limit the damage, but he has much to do with seven shots separating him and Els.
Harrington said: "I'm happy with my scoring, but I made a few mental errors out there and missed a few putts.
"Obviously, though, I hit enough good shots and I seemed to have a lot of reasonable chances for birdies."
His only dropped shot came after he hooked his drive into the lake on the treacherous 18th, his ninth of the day.
England's Lee Westwood enjoyed the best day of any Briton leaping up the leaderboard with a much-improved 68 after an opening-round 74.
At the front of the pack Australian Allenby had threatened the course record in his first round before coming to grief with four bogeys over the final four holes.
This time a double-bogey six out of the sand on 16 cost him the lead after a hole-in-one on the 13th and birdie on the 14th.
By contrast Els was a model of consistency as he signed off on a round that featuring six birdies and was unblemished by bogeys.
The three-time major winner's performance comes only a week after a dismal showing at the Honda Classic where he finished in joint-67th and failed to break par in any of his four rounds.
But Els believes a reduced travel schedule has given him the chance to fix the faults in his game.
"I didn't have it last week so I worked really hard Saturday, Sunday, Monday, Tuesday and Wednesday," he said.
"I did find something, so I'm sticking with it. By Wednesday it started feeling a bit more comfortable and now I feel I can hit the ball with more authority and keep the ball flight down."