MELBOURNE, Australia (CMC): Another wretched batting collapse left a deflated West Indies hanging by a string against Australia and staring another humiliating defeat in the face after only two days of the pivotal second Test. Under severe pressure after Australia piled up a daunting 551 for three declared in their first innings, the Windies displayed little character in reply, and their innings lay in ruins at 91 for six, on a chastening day at the Melbourne Cricket Ground. There were initial hopes the tourists would banish the nightmares of the Hobart first Test, when opener Rajindra Chandrika, who made 25, and partner Kraigg Brathwaite, who got 17, added 35 for the first wicket. But West Indies lost wickets in clusters. Three tumbled for 15 runs to leave them tottering on 50 for three, and after Jermaine Blackwood, who struck 28, and Darren Bravo (13 not out) put on 32 for the fourth wicket, the Caribbean side lost another three wickets for a single run in the space of 15 deliveries, to crumble again. The damage was done by left-arm spinner Nathan Lyon (2-18), along with fast bowlers Peter Siddle (2-19) and James Pattinson (2-36), all of whom picked up two wickets apiece to wreck the Windies innings. Left-hander Bravo, who has faced 75 balls in a defiant knock, will carry his side’s fight on the third day along with debutant all-rounder Carlos Brathwaite, who was unbeaten on three. Captain Steve Smith had earlier punched his sixth century of the year and 13th of his career with an unbeaten 134, while Adam Voges, at age 36, notched his fourth century of his debut year, as Australia built on their overnight 345 for three. The right-handed Smith, unbeaten on 32 at the start, struck eight fours in an innings lasting 177 balls, while Voges counted 12 fours off 166 deliveries, to follow up his brilliant unbeaten 269 in Hobart. Together, they posted 223 in an unbroken fourth-wicket partnership as the Aussies added a further 206 before declaring an hour before tea, with West Indies all but deflated. Fast bowler Jerome Taylor, who bowled just four overs on Sunday, finished with two for 97.