The Proteas capitulated against rampant top-ranked Australia on Thursday to lose the second Test in Melbourne by an innings and 182 runs and with it the series.SCOREBOARD | Proteas v Australia - 2nd TestIt capped a dismal first two Tests for the Proteas who slumped by six wickets in the opener at Brisbane inside two days, with a potential face-saving third match at Sydney still to play.They resumed day four on 15-1 after skipper Dean Elgar was caught by Alex Carey off Pat Cummins for a duck before rain halted play early on Wednesday.But their resistance didn't last long with three wickets falling before lunch at the Melbourne Cricket Ground and the rest in the second session as they meekly succumbed for 204.Temba Bavuma top-scored with 65 while Nathan Lyon took 3-58 in a depleted, injury-hit, attack.It leaves South Africa facing a trip to Sydney next week for the final Test with only pride to play for and potentially some changes to a batting line up that has largely failed to fire.Australia will have a new-look team with Cameron Green and Mitchell Starc already ruled out as they race the clock to be ready for a blockbuster series in India in February.Josh Hazlewood is set to return in Sydney after recovering from a side strain, declaring Thursday he was fit after missing the last two Tests, with Green's replacement to be decided.Theunis de Bruyn (28), Sarel Erwee (21) and Khaya Zondo (one) all departed before lunch at the hands of Australia's high-class pace attack.Then the spin of Nathan Lyon, and two careless run outs, ended any hope they had in the second session.Australia declared on Wednesday at 575-8 built on the back of man-of-the-match David Warner's 200 in reply to South Africa's first innings 189 and then took