Michael Robertson crossed for two tries as Manly prepared for the World Club Championship by squeezing past a determined Harlequins at the Stoop.

But it required a second-half fightback from the first-choice 13 after an experimental line-up trailed 20-0 at the interval.

Manly, who had seen their squad suffer bouts of flu during the week, elected to start with a number of fringe players and debutants, and were hit by a Harlequins burst of three tries in a 10-minute spell early in the first-half.

After six minutes Jon Wells profited from a Danny Orr kick to canter over after Matt Gafa had been held up over the line.

Eight minutes later quick thinking saw skipper Rob Purdham crash over, and straight from the restart a Will Sharp break allowed Chad Randall to cross.

Manly were struggling to find any rhythm, and it took them until the half-hour mark to trouble the home line.

There was still time for the Londoners to add to their lead before the interval, Luke Dorn racing on to a clever Purdham kick to stroll under the posts. Orr was successful with the conversion.

Manly coach Des Hasler shook things up at the break and elected to unleash his side's big guns, with skipper Matt Orford, Jamie Lyon and Brett Stewart coming off the bench.

Orford had an immediate impact with a perfectly weighted cross kick which Michael Robertson claimed to score.

Robertson was on hand seconds later to cross for his second as the Australians ate into the Quins lead.

Jamie O'Callaghan touched down to increase Quins' advantage but the Sea Eagles had their tails up and quick-fire touchdowns by David Williams and Brett Stewart narrowed the gap to just four points.

The pressure finally told 10 minutes from time when some great hands allowed Lyon to dive over.

Steve Matai crossed in the final moments to seal the victory.