HANOI, July 16 (Reuters) - Holders Japan stormed into the Asian Cup quarter-finals with a clinical 4-1 demolition of co-hosts Vietnam on Monday.

But Vietnam, appearing in the tournament for the first time

in 47 years, joined Japan in the last eight after Qatar lost

2-1 to United Arab Emirates in the other Group B game.

'I'm still not satisfied,' Japan coach Ivica Osim told

reporters. 'If I was satisfied then I might as well just quit

as coach.'

Japan's reward for finishing top of their group is a grudge

quarter-final against Australia, who avoided an early exit with

a 4-0 win over Thailand in Bangkok later on Monday.

A Keita Suzuki own goal put Vietnam ahead after just seven

minutes and triggered riotous celebrations among a crowd of

40,000, but it took Japan just five minutes to restore normal

service.

Celtic midfielder Shunsuke Nakamura found space on the left

to float over a perfect cross for Seiichiro Maki, who had the

simple task of chesting the ball into an open goal.

Yasuhito Endo put Japan ahead just after the half hour,

rifling a free kick into the top corner from the edge of the

box to briefly silence Vietnam's trumpet-blowing fans.

Nakamura added a third seven minutes into the second half

with a superb right-foot strike before Maki headed in his

second from close range in the 59th minute.

Maki told Reuters Japan were happy to get the opportunity

to avenge their 3-1 defeat by the Socceroos at last year's

World Cup in Germany.

'If we'd have a choice of opponents, Australia would have

been first on the list,' he smiled. 'That's the team we wanted

to meet and have the chance to bury those ghosts.'

When news of UAE's win over Qatar in Ho Chi Minh filtered

through, Hanoi's My Dinh stadium erupted in a deafening roar as

Vietnamese fans began to celebrate wildly.

'It's a sensation,' beamed Vietnam coach Alfred Riedl.

'Nobody expected us to be in the quarter-finals. It's the first

time Vietnam's history.

'I'm extremely proud of my players and maybe Vietnam will

surprise again.'

Japan, bidding for a third straight title, finished top of

Group B on seven points with Vietnam runners-up on four. UAE

were third on three points with Qatar on two.

Japan play Group A runners-up Australia in Hanoi on

Saturday, while Vietnam travel to Bangkok to face Iraq.