Qatar champions Lekhwiya have been left with a huge mountain to climb after crashing to an embarrassing 4-1 defeat to Saudi giants Al Hilal in the first leg of their AFC Champions League quarter-finals on Tuesday.

At an empty King Fahd Stadium in Riyadh, Lekhwiya, who have won the Qatar Stars League four times in the last five years, appeared rusty despite their lengthy pre-season camp in Europe and fell behind to a 11th-minute goal from Brazilian striker Ailton who took full advantage of a grave blunder by goalkeeper Amine Lecomte.

French-Moroccan Lecomte unnecessarily delayed clearing the ball on the edge of his own penalty area, and when he finally took the shot, the ball struck Ailton and bounced into the net much to the goalkeeper's embarrassment.

Lekhwiya though pulled level within six minutes through Youssef Msakni who profited from a great pass by Nam Tae-hee, before Khalid al-Kaabi made it 2-1 in the 33rd minute.

Carlos Eduardo then made it 3-1 three minutes later before registering his second goal of the match in the 85th minute to complete the rout.

Earlier on Tuesday, Paulinho scored a stunning free-kick from 40 metres as Luiz Felipe Scolari's Guangzhou Evergrande thumped Kashiwa Reysol 3-1 to put one foot in the semi-finals.

An early own goal by Kashiwa captain Daisuke Suzuki put the visitors ahead before the wonder-strike from the Brazilian midfielder signed from Tottenham Hotspur in June.

Gao Lin extended Guangzhou's advantage with a towering header early in the second half before Masato Kudo cut the deficit with a close-range effort late in the game.

But barring a miraculous turnaround in the quarter-final's second leg in China on September 15, Guangzhou will go into a last-four clash against Jeonbuk Hyundai Motors or Gamba Osaka.

Scolari was hired by the Chinese champions in June, looking for a new start a year after he led Brazil to their humiliating 7-1 World Cup semi-final defeat to Germany.

Guangzhou won 4-1 at Hitachi Kashiwa Stadium in the semi-finals two years ago, en route to lifting their first continental title, and they got an early boost when Suzuki deflected Huang Bowen's free-kick past goalkeeper Takanori Sugeno after only five minutes.

Scolari's side dominated proceedings in the opening half and they duly increased their lead five minutes before half-time when Paulinho scorched his free-kick into the top corner past a static Sugeno.

Guangzhou appeared to put the tie to bed in the 58th minute when Huang swung in a cross from the left and his Chinese international team-mate Gao rose above the Kashiwa defence to head the ball home.

Kashiwa struggled to create chances but Kudo gave them some hope when he bundled the ball into the net in the 89th minute after Suzuki had dived low to flick a corner across the goalmouth.