Holland star Arjen Robben sustained a serious hamstring injury that could well prevent him from taking part in the World Cup. The Bayern Munich winger hurt himself in Holland's 6-1 friendly win over Hungary when he attempted a back-heel pass and fell awkwardly in the process. Robben, who was introduced as a second-half substitute and bagged a brace before picking up the injury, limped off instantly five minutes from time. The full extent of Robben's problem is yet to be determined but coach Bert Van Marwijk is not optimistic over the 26-year-old's chance to be fit for the imminent World Cup. "He felt a sharp pain, that can't be good," the Holland boss said. "Treatment for these injuries has improved hugely, so I'm not giving up hope yet. "I thought to myself, 'This can't be true. He made an unnatural movement and injured his hamstring." Robben, who has been instrumental in helping Bayern claim the Bundesliga title and finish their UEFA Champions League as runners-up, won't travel to South Africa along with Holland's contingent on Saturday in order to undergo scans the next day. Robben's awkward back-heel pass: