China saved a second half penalty then scored a fortuitous goal that took a wicked deflection off a defender to upset Saudi Arabia 1-0 at the Asian Cup on Saturday.

Two days into the tournament, everything had gone according to plan, but China tore up the script at Lang Park by producing the first real upset of the event.

Midfielder Yu Hai got the only goal of the match when he banged his free-kick into the back of the net 10 minutes from the end, but only after a stroke of luck.

His left-footed shot from 30 metres out clipped the back of one of the Saudi defenders and deviated away from the helpless Saudi goalkeeper Waleed Abdullah.

The Chinese surprisingly dominated the first half but almost fell behind in the second term when the Saudis were awarded a penalty after striker Naif Hazazi was hacked down by Ren Hang as he was bearing down on goal.

But Hazazi made a hash of his spot kick, lamely booting it straight into the legs of the Chinese goalkeeper Wang Dalei, who was mobbed by his team mates after making the save.

Although Saturday's match was the first of the tournament for both teams, the result could prove decisive to both team's chances of progressing after Uzbekistan, the Group B favourites, earlier beat North Korea 1-0 in Sydney.

The Saudis, one of Asian football's traditional giants, went into the match as heavy favourites but failed to impose themselves against a Chinese team that was lucky to make for the 16-country tournament, advancing only as the best third-places team in the qualifying groups.

Despite having won the Asian Cup three times, the Saudis have struggled in recent years, losing all three of their group matches at the 2011 tournament and slipping to 102nd in the world rankings, six places below China.

The Chinese, chasing a first Asian Cup title, succeeded in prising open the Saudi defence several times and delivered some quality crosses, though few resulted in clear-cut scoring chances.

The best opportunity to break the deadlock fell to Chinese midfielder Wu Xi three minutes before the interval when he found himself in space near the box but he shot wide.