Gulf rivals Saudi Arabia and Oman played out an entertaining 1-1 draw in Singapore on Sunday as the two sides stepped up their preparations for the AFC Asian Cup.

Substitute Mohammed Al Shalhoub opened the scoring for the Saudis after 55 minutes but Oman drew level on the hour mark as Fawzi Bashir rose to head home an Ahmed Hadid free-kick.

The match went to a penalty shootout and the Omanis triumphed by a 3-1 margin.

Saudi Arabia could have broken the deadlock as early as the sixth minute when Abdoh Autef played a defence-splitting pass towards Nassir Al Shamrani only for Oman goalkeeper Ali Al Habsi to come off his line to clear the danger.

Oman worked an excellent opening after 20 minutes as Mohamed Saleh Al Ghassani sent in a cross from the right to an unmarked Ismail Al Ajmi whose unchallenged header from eight yards went straight into the arms of goalkeeper Waleed Abdullah.

Al Habsi was called into action again on 33 minutes when the ball was worked to Saleh Bashir on the right edge of the Omani area and the Saudi striker unleashed a hard low shot but the Omani keeper got down well to parry away the attempt.

He would be grateful to the assistant referee's flag just a minute later as Ibrahim Hazzazi rose to head home an Abdulrahman Al Qahtani free-kick only to see the effort chalked off for offside.

Al Shalhoub replaced Al Qahtani at half-time and the Saudi substitute made an impact just 10 minutes after his introduction, racing into the Omani box to meet Al Shamrani's inch-perfect pass and calmly clipping the ball past Al Habsi to give his side a 1-0 lead.

The Saudi lead would only last for five minutes as Oman drew level on the hour after Ahmed Hadid floated in a free-kick from the left flank that was met in the box by Bashir with a powerful header that gave Abdullah no chance.

Oman could have gone ahead just two minutes later when Hassan Yousuf Madhafar's cross from the left was glanced across goal by Imad Ali but Abdullah made an excellent reflex save to turn the ball around the post.

A slip by Redha Tukar nearly proved costly for the Saudis with 13 minutes remaining as the central defender coughed the ball up to Imad Ali, who raced from midfield and beat Abdullah only for Hazzazi to clear the ball off the line.

With five minutes remaining, Abdullah was called into action yet again to tip over a free-kick by Hussain Al Hadhri.

Abdullah would also deny Ismail Al Ajmi in the penalty shootout, but Al Habsi saved efforts by Kamil Al Mousa and Khaled Aziz before Malek Maaz blasted his attempt wide to give Oman victory.

The match was the penultimate warm-up match for both sides before they begin their Asian Cup campaigns.

Oman face S-League side Woodlands Wellington on Monday before leaving for Bangkok for their opening Group A match against Australia on July 8, while the Saudis take on DPR Korea in Singapore on Wednesday before travelling to Indonesia to face Korea Republic in their Group D opener on July 11.