The hosts had already won both of their opening matches and secured their passage through to the quarter finals, at an event which is doubling as a Rio 2016 qualifier, by maintaining their 100 per cent record.

They didn't have it all their own way though as Syria, who needed to win to keep their own last eight hopes alive, took a fourth minute lead thanks to Yousef Kalfa.

Their lead only lasted six minutes as Abdelkarim Hassan netted after ten minutes before Ahmed Alaa put the Qataris in front.

Syria were reeling and things got worse for them when the 2022 FIFA World Cup hosts added a third shortly before the half-hour mark, courtesy of Moez Ali.

Qatar now looked comfortable but Syria threatened an unlikely comeback when Omar Khribin converted from the penalty spot with nine minutes left.

Any home fears were eased, however, as Alaa struck again just a minute later.

"It is obviously not the start of the game we expected, we were a bit sleepy in the beginning of the game and our opponents were pushing and we received a goal, but the mentality of the team was very good after we conceded,” said Qatar coach Felix Sanchez.

“We scored three and this gave us the rhythm of the game and I think in the second half we created many chances to score more goals and finally it was 4-2 and I am proud of the players for their effort.

"It is amazing against a team who it is difficult to play against, but I think we deserved the result.

“Our aim is the next game which is the quarter-final and there is no second chance.

"The players are highly motivated and looking forward to play in the next game and to win to be in the semi-final.”

Meanwhile, Iran also qualified by beating pointless China 3-2 at the Abdullah bin Khalifa Stadium to finish in the runners-up berth.

Arsalan Motahhari gave the Iranians the lead on 38 minutes before Chang Feiya levelled seconds later.

Ehsan Pahlavan restored his side’s lead before the break in a frantic three-minute spell late in the first half, before Mahdi Torabi’s free kick just after the break extended Iran’s advantage to 3-1.

A penalty by Liao Lisheng caused some late jitters but proved to be only a consolation.

Qatar will find out their quarter-final opponents tomorrow when Group B concludes, although Iran know that they will face Japan as they have already been confirmed as table toppers.

Saudi Arabia, currently second on two points, are facing the Japanese, who have six, while North Korea and Thailand, who both have one point, will meet with each side still in with a chance of going through.

The top three teams at the tournament will qualify for the Rio 2016 Olympics this summer.