Jacques Rogge has defended the controversial ticketing policy adopted by Olympic Games organisers for London 2012.
The London Organising Committee of the Olympic Games used a balloting system to process what has proven an unprecedented demand for tickets at an Olympics.
But with two million people making 22 million ticket applications when only seven million are available, many missed out completely.
Speaking at the official year-to-go celebrations at the newly-completed Aquatic Centre in Stratford, International Olympic Committee president Rogge said: "I understand the disappointment of those who didn't get a ticket.
"That's the cruelty of the lottery system. But a lottery system is an open, transparent and fair one.
"It was so oversubscribed that people are bound to be disappointed. The good side is that the venues will be fully packed and this is very important."
Rogge declared himself "a very happy man" after visiting the Aquatics Centre.
He described the £269million arena as "a masterpiece" and applauded London 2012 organisers for finishing the last of the six main permanent Olympic Park venues 12 months ahead of the opening ceremony.
He praised the work done so far but also warned against complacency.
He said: "London has done a great job. I am confident that London will deliver a great Games."
