Japan head coach Hajime Moriyasu is showing patience with an Asian Cup campaign that is yet to truly catch fire.

The Blue Samurai made it four wins out of four in the United Arab Emirates as they edged past Saudi Arabia 1-0 to book a quarter-final against surprise package Vietnam.

Indeed, all of Japan's victories have come by a single-goal margin but Moriyasu insists his team are a work in progress.

"Japan is here and we aim to win the title, but the team needs to be developed because we have some new players who are lacking experience," he told reporters ahead of a game where he will be without Newcastle United forward Yoshinori Muto through suspension.

"We are playing each match and learning from them. We know [Vietnam] will be a difficult match but we'll do our best and bring the confidence of having won our four matches."

Vietnam defender Luong Xuan Truong is eyeing another upset after Park Hang-seo's side overcame Jordan on penalties in the last 16.

 "We are very happy right now because we made another piece of history for Vietnamese football," he told AFC.com.

"[The game against Jordan] was amazing.

"I hope we can keep playing in the same way against the next opponent and hope we can make more history for Vietnam."

Vietnam have won their three most recent shoot-outs, with Xuan Truong on target in each.

"I think we can't say anything about a penalty shoot-out because we never know before a game, what's going to happen," he added

"We were luckier than Jordan, and I think that's all it is."

PLAYERS TO WATCH

Dang Van Lam (Vietnam)

If this one also goes to the wire, Vietnam will look to Van Lam to be their hero once more after his brilliant save from Ahmed Saleh to break Jordanian hearts.

Yuya Osako (Japan)

The Werder Bremen forward opened the tournament with a brace against Turkmenistan. He has not featured since due to muscular problems but Muto's absence could pave the way for a return.

Key Opta facts:

- This will be the second meeting between Vietnam and Japan in the Asian Cup, Japan coming from 1-0 down to win 4-1 in the 2007 group stages.
- Vietnam's only previous venture into quarter-final stage came in the same tournament, when they lost to eventual winner Iraq.
- Vietnam have recorded the lowest possession figures of any team left in the 2019 Asian Cup (48.6 per cent).
- Only Iran (15) have scored more goals from set-piece situations than Japan (14) since the 2007 Asian Cup.
- Japan have had six different goalscorers in the 2019 Asian Cup – more than any other side in the competition.