Johannesburg: The South Australia Redbacks made sure of finishing top of their group when they beat Guyana by 15 runs in a Champions League Twenty20 match at the Wanderers Stadium.Callum Ferguson hit 55 and added 88 for the fourth wicket with Cameron Borgas (48) to enable the Redbacks to reach 191 for six after a poor start in which they lost their first three wickets for 41 runs.Guyana captain Ramnaresh Sarwan hit 70 as Guyana made 176 for seven in reply.The win meant the Redbacks finished top of Group B with four wins from four matches.Captain Michael Klinger said it was an advantage because they can remain based in Johannesburg for the remainder of the tournament because they will play in the second semi-final against the runners-up in Group A at nearby Centurion on Saturday.The final is at the Wanderers on Sunday.If they had finished second in the group the Australian side would have had to travel to Durban to play in the first semi-final on Friday.Klinger admitted that his side had not played as well as they had in earlier matches.'We need to pick up a little bit before the semi- final but we know that and we'll work on it in the next few days. Our fielding was a touch down today.'South Australia were without fast bowler Shaun Tait because of a minor shoulder injury but Klinger said Tait would definitely play on Saturday.Guyana finished the tournament with four defeats from as many games but they were competitive for much of Tuesday's game.'We showed what we are capable of,' said Sarwan.'It's unfortunate we couldnât do it throughout the tournament.'