Mat Ryan was Australia's hero with two fabulous shoot-out saves as the Asian Cup holders saw off Uzbekistan 4-2 on penalties after a turgid 0-0 draw in the last 16.

The White Wolves' star man Eldor Shomurodov came closest to breaking the deadlock before half-time.

Australia's threat was negligible against a team ranked 95th in the world until Mathew Leckie came on for his first appearance of an injury-ruined tournament.

Leckie and Tom Rogic provided Graham Arnold's men with fresh impetus and it was the Hertha Berlin winger who coolly dispatched the decisive penalty after Ryan thwarted Islom Tukhtakhujaev and Marat Bikmaev in style.

Shomurodov was Uzbekistan's best attacking outlet and embarked upon a jinking run from the left into the Australia box, giving Ryan his first work in the 10th minute.

The Socceroos managed to get on the front foot after the break, with Jamie Maclaren having a shot blocked from Awer Mabil's clever throughball and Rhyan Grant unable to get enough purchase on his header from the rebound.

Right-back Grant darted in at the back post to nod over with an hour played before the relatively lively Mabil made way for Leckie.

Maclaren was unable to get a touch when Rogic slid a ball through the Uzbekistan backline and was replaced by Apostolos Giannou with 15 minutes to play.

Davron Khashimov hacked out of his goalmouth after Leckie cut inside to have a shot saved, while Uzbek captain Odil Ahmedov had a volley deflected wide on a rare 86th-minute attack.

Leckie fired into the arms of Ignatiy Nesterov after the goalkeeper saved Rogic's drive early in extra-time and the Celtic midfielder hacked wide at the end of a solo run as he sought to avert the need for spot-kicks.

Australia left-back Aziz Behich will have wished he had when Nesterov made the first save of the shoot-out, but Ryan came to his and his country's rescue.

What does it mean? Holders still searching for top gear

Australia skipper Mark Milligan, and substitutes Robbie Kruse and Giannou finding the target before Leckie sealed progression ensured the Socceroos remain on course to retain their title. Whether the likes of Iran, South Korea or Japan would have much to fear from them in this form is a moot point. Uzbekistan miss out on the quarter-finals for the first time since 2000.

Ryan underlines top-class credentials

Much will be made once again of Australia lacking inspiration when it comes to breaking the opposition down but the last line of their defence is in safe hands with the ever-improving Ryan, who underlined the strides he has made in the Premier League over the past 18 months. He won a battle of wits with Tukhtakhujaev, remaining in the centre of his goal to repel a powerful strike, while the athleticism and strength on show to keep Bikmaev's penalty out of the bottom left corner was top drawer.

Arnold's vision no closer to taking shape

Former Australia boss Ange Postecoglou collected his share of critics on account of a brusque style with the media and an unflinching commitment to an expansive attacking football, sometimes to a cavalier degree. However, he masterminded 2015 Asian Cup glory and his sides were never less than worth watching. It cuts a sharp contrast with the latest torpid slog under Arnold, whose reputation as a two-time A-League winner is one of few factors to inspire belief at this stage.

What's next

Australia will face the winner of the last-16 clash between hosts United Arab Emirates and Kyrgyzstan at Zayed Sports City Stadium later on Monday.