By Mark Gleeson LONDON (Reuters) -Australia took control of the World Test Championship final on Thursday as they stretched their lead over South Africa to 106 runs at tea on the second day after captain Pat Cummins had taken six wickets.

Pat Cummins said the World Test Championship final was a good advertisement for Test cricket despite a likely finish within three days.

Lungi Ngidi (3-35) was the chief destroyer after a quiet first innings, claiming the prized scalp of Steve Smith (13), Beau Webster (9) and Aussie skipper Cummins (6) amid a potentially match-defining nine-over spell post-tea.

Cummins' 6 for 28 in the second innings of the WTC final was also the best figures by a Test captain at Lord's

South Africa were reeling on 43-4 at stumps on the first day of the World Test Championship final at Lord’s on Wednesday after dismissing defending champions Australia for 212. Seamer Kagiso Rabada took 5-51 as South Africa’s bowling unit made a strong start to the match but their inexperienced batting line-up came under fire as soon as they began their reply.

Cummins brought up his 14th five-wicket haul on the way to picking a sensational 6-28 to help bundle out South Africa for 138 in 57.1 overs on the second day at the iconic Lord's Cricket Ground on Thursday.

There will be a fortnight's break as the county plays T20 fixtures which Murphy, who plays in the BBL with the Sydney Sixers, is not signed for, before two matches in Cheltenham, against Lancashire and Middlesex to end his stint.

Steve Smith led an Australia fightback to put the defending champions on 190-5 at tea on the opening day of the World Test Championship final against South Africa at Lord’s on Wednesday. Smith scored