US Open champions Marin Cilic and Serena Williams kicked off their China Open campaigns with straight sets victories against battling underdogs on Monday, but Rafael Nadal suffered defeat in a rare doubles outing on his return from injury.
It will have made uneasy viewing for coach Jorge Sampaoli and emphasised more than ever how reliant his side are on their talisman Messi, who has been struggling with a muscle problem.
