JOHANNESBURG — Left-arm spinner Ashton Agar took a hat-trick as Australia crushed South Africa by 107 runs in the first Twenty20 international at the Wanderers Stadium on Friday. Steve Smith, back in South Africa for the first time since the 2018 ball-tampering scandal, hit a top score of 45 for Australia, who made 196 for six after being sent in. South Africa made a bad start against the pace of Mitchell Starc and Pat Cummins before Agar"s triple strike sent them hurtling to an all-time lowest T20 total of 89. It was also the host country"s biggest defeat in the format. Agar had career-best figures of five for 24. Starc made a crucial breakthrough when he bowled South African captain and batting star Quinton de Kock for two with a fast, swinging delivery in the first over of the home side"s reply. South Africa were reeling at 40 for four when Agar came on to bowl. He had Faf du Plessis caught at deep cover with his fourth delivery, trapped Andile Phehlukwayo leg before next ball and Dale Steyn superbly caught at slip by captain Aaron Finch to complete the hat-trick. Agar, who was declared the man of the match, said: “It was really exciting; a highlight of my cricketing life. It was made easy by Starc, Cummins and Richardson bowling in front of me. Starc, at 150 clicks, induces fear in the opposition. I was feeling horrible at the start of the game. But with a bit of turn off the pitch your job becomes easy. Terrific catch by the skipper, he enjoyed it himself.” Finch, the winning skipper, too was happy for Agar and the way the Australians played as a team. “The way we set the tone on the field was fantastic. Ashton gets the credit today; the lengths he bowled was fantastic. When you are scoring 200 the start is very important. I would have batted second as well had I won the toss, so a nice toss to lose. “I thought the way we attacked the crease and the lengths we bowled was fantastic. If someone blasts a good ball off you, you take your hat off to them. I had a 10% chance of catching that (hat-trick ball) but he deserves all the credit." A bemused South African captain Quinton de Kock said, "I am not quite sure what happened here." He lamented the fact that there was no energy. "The energy was there but the skills just weren"t enough. Obviously we try and pride ourselves with our fielding and we weren"t at our best today. There isn"t much you can do at practice, it has to be a mental thing for the boys. We hope to come back with that fight on Sunday." Earlier, Smith, back in South Africa for the first time since the 2018 ball-tampering scandal, put on 80 runs for the second wicket with Finch to provide the foundation for Australia"s strong total. Finch hit powerfully to make 42 off 27 balls and Smith scored 45 off 32 deliveries after Australia lost David Warner to the second ball of the match, caught at fine leg off Dale Steyn. The pair put on 80 off 52 balls before Finch was caught in the deep off left-arm wrist spinner Tabraiz Shamsi. Smith was lucky to survive when a top-edged cut off Lungi Ngidi flew towards Steyn at third man. Steyn lost sight of the ball and it dropped over his head to go for four — Smith"s first runs. Friday"s game is the first in South Africa for Smith and Warner since March 2018 when they were banned for ball-tampering in the third Test in Cape Town. Smith was Australia captain and Warner his deputy at the time. Australia, who were sent in, lost wickets at regular intervals on Friday but managed to maintain a rapid scoring rate against a South African bowling attack which conceded 12 wides and struggled to maintain a consistent line and length. Veteran fast bowler Steyn and Shamsi were South Africa"s best bowlers, both taking two for 31 in four overs. Fast bowler Kagiso Rabada was erratic on his return to action after being rested for the recent one-day and T20 series against England. He conceded 45 runs in three overs. Scoreboard Australia D. Warner c Shamsi b Steyn 4 A. Finch c Du Plessis b Shamsi 42 S. Smith st De Kock b Shamsi 45 M. Wade c Miller b Steyn 18 M. Marsh c Steyn b Ngidi 19 A. Carey c Du Plessis b Phehlukwayo 27 A. Agar not out 20 M. Starc not out 7 Extras (lb2, w12) 14 Total (6 wkts, 20 overs) 196 Did not bat: P. Cummins, K. Richardson, A. Zampa Fall of wickets: 1-4 (Warner), 2-84 (Finch), 3-114 (Wade), 4-117 (Smith), 5-167 (Carey), 6-171 (Marsh) Bowling: Steyn 4-0-31-2 (2w), Ngidi 3-0-37-1 (1w), Rabada 3-0-45-0 (2w), Phehlukwayo 4-0-35-1 (2w), Shamsi 4-0-31-2 (5w), Smuts 2-0-15-0 South Africa Q. de Kock b Starc 2 H. van der Dussen c Starc b Cummins 6 F. du Plessis c Richardson b Agar 24 J. Smuts c Zampa b Cummins 7 D. Miller c Carey b Zampa 2 P. van Biljon b Agar 16 A. Phehlukwayo lbw b Agar 0 D. Steyn c Finch b Agar 0 K. Rabada b Zampa 22 L. Ngidi c Warner b Agar 1 T. Shamsi not out 2 Extras (w7) 7 Total (14.3 overs) 89 Fall of wickets: 1-2 (De Kock), 2-17 (Van der Dussen), 3-38 (Smuts), 4-40 (Miller), 5-44 (Du Plessis), 6-44 (Phehlukwayo), 7-44 (Steyn), 8-77 (Van Biljon), 9-85 (Ngidi), 10-89 (Rabada) Bowling: Starc 3-0-23-1 (3w), Richardson 3-0-20-0, Cummins 2-0-13-2, Zampa 2.3-0-9-2, Agar 4-0-24-5. — AFP