Cape Town - South African duo Branden Grace and Justin Harding won their opening group matches at the World Golf Championships-Match Play.
Grace prevailed over Japan's Hideki Matsuyama 4&3 and will face world No 1 Dustin Johnson on Day 2 at the Austin Country Club.
"It's going to be a tough match ... It's going to be good," Grace told the PGA Tour website.
"If I keep doing the same things that I've done today, ball-striking was a big key ... I'll head to the putting green. I missed one or two little short ones. So if I can get that under control, I'll be there."
The in-form Harding took down Englishman Matthew Fitzpatrick 1-up. However, the South African will have his work cut out for him when he battles world No 4 Rory McIlroy on Thursday.
"I'm going to have to improve a little bit to take him on," Harding told the PGA Tour.
"Rory's been playing great over the last couple of weeks. It will be a nice opportunity for me to see how it's done inside the ropes, and maybe learn a little bit as well, and give the boy a little bit of a challenge."
Meanwhile, SA's top ranked golfer Louis Oosthuizen lost 3&2 to American Kyle Stanley.
Oosthuizen will be desperate for a win on Thursday when he takes on South Korean Byeong Hun An as it's impossible to advance out of the group stage with two defeats.
Results from Wednesday's opening matches of the WGC Match-Play Championship at Austin (Texas) Country Club (Group winners advance to knockout stage):
Dustin Johnson (USA x1) bt Chez Reavie (USA x55) 4&3
Branden Grace (RSA x40) bt Hideki Matsuyama (JPN x24) 4&3
Justin Rose (ENG x2) bt Emiliano Grillo (ARG x53) 2&1
Gary Woodland (USA x22) bt Eddie Pepperell (ENG x34) 2&1
Brooks Koepka (USA x3) and Tom Lewis (ENG x60) halved
Li Haotong (CHN x36) bt Alex Noren (SWE x27) 5&4
Rory McIlroy (NIR x4) bt Luke List (USA x64) 5&4
Justin Harding (RSA x47) bt Matthew Fitzpatrick (ENG x32) 1-up
Lucas Bjerregaard (DEN x50) bt Justin Thomas (USA x5) 3&2
Matt Wallace (ENG x33) bt Keegan Bradley (USA x31) 1-up
Bryson DeChambeau (USA x6) bt Russell Knox (SCO x59) 3&1
Marc Leishman (USA x17) bt Kiradech Aphibarnrat (THA x39) 2-up
Francesco Molinari (ITA x7) bt Satoshi Kodaira (JPN x63) 5&4
Thorbjorn Olesen (DEN x45) bt Webb Simpson (USA x21) 2&1
Jon Rahm (ESP x8) bt Ki Si-woo (KOR x54) 7&5
Matt Kuchar (USA x23) bt JB Holmes (USA x43) 3&1
Xander Schauffele (USA x9) bt Lee Westwood (ENG x62) 1-up
Tyrrell Hatton (ENG x35) bt Rafa Cabrera Bello (ESP x29) 4&3
Paul Casey (ENG x10) bt Abraham Ancer (MEX x58) 5&3
Charles Howell (USA x42) bt Cameron Smith (AUS x25) 2&1
Tommy Fleetwood (ENG x11) bt An Byeong-hun (KOR x49) 3&2
Kyle Stanley (USA x41) bt Louis Oosthuizen (RSA x19) 3&2
Jim Furyk (USA x52) bt Jason Day (AUS x12) 2-up
Henrik Stenson (SWE x37) bt Phil Mickelson (USA x20) 2&1
Tiger Woods (USA x13) bt Aaron Wise (USA x61) 3&1
Patrick Cantlay (USA x18) and Brandt Snedeker (USA x44) halved
Tony Finau (USA x14) bt Keith Mitchell (USA x56) 2&1
Ian Poulter (ENG x30) bt Kevin Kisner (USA x48) 2-up
Kevin Na (USA x57) bt Bubba Watson (USA x15) 1-up
Jordan Spieth (USA x28) and Billy Horschel (USA x38) halved
Andrew Putnam (USA x51) bt Patrick Reed (USA x16) 3&2
Sergio Garcia (ESP x26) bt Shane Lowry (IRL x46) 4&2