Ralston's seven leads to WC rout

Australia have romped to the second-biggest victory in Under-19 World Cup history after defeating Papua New Guinea by 311 runs to secure qualification for the tournament's quarter-finals in New Zealand.

After opener Nathan McSweeney smashed 154 off just 111 balls to fire Australia to 8-370 from their 50 overs, fast bowler Jason Ralston claimed 7-15 off 6.5 overs, the best figures ever recorded at a U19 World Cup.

Papua New Guinea lasted just 24.5 overs and were skittled for 59, with No.7 Leke Morea (20) the only batsman to reach double figures.

McSweeney smashed 18 fours and four sixes in his 111-ball knock as he notched up the second-highest innings of the tournament, behind New Zealand's Jakob Bhula's 180 against Kenya on Wednesday. 

The young Australians were in early trouble at 1-3 after Max Bryant was bowled by a Sema Kamea yorker, however McSweeney and Jason Sangha (88) piled on 250 for the second wicket.

Param Uppal blasted 61 off 42 balls as Australia piled on 169 runs from their final 20 overs.

Ralston, a right-arm quick from Wollongong, then eclipsed Sri Lankan Jeevan Mendis' best-ever U19 World Cup figures of 7-19, which he took against Zimbabwe at the 2002 edition of the tournament also held in New Zealand.

Only India's Irfan Pathan, who took 9-16 against Bangladesh in the 2003 U19 Asia Cup, has recorded better figures in a youth ODI.

Australia's 311-run winning margin is second only to their 430-run victory over Kenya U19s in 2002, where a Cameron White, Shaun Marsh and George Bailey-led side racked up 480 and bowled their opponents out for 50.

Australia U19s locked up second spot in Group B with their win over PNG on Friday and will advance to the quarter-finals where they will likely meet England next Tuesday.