July 17 (Reuters) - With World Championship titles and the 400-metre hurdles world record in his possession, there is only one jewel left for Karsten Warholm to add to his athletics crown: Olympic gold. Yet it could be the hardest test the 25-year-old Norwegian has faced so far. "You have to be at a world-record level to be able to compete for a gold medal in Tokyo," Warholm told reporters in the lead up to the Games. "There is no doubt about that. But what the time is going to be, that"s hard to tell - and only time will show." In front of an ecstatic, home crowd earlier this month, Warholm ran 46.70 seconds to break Kevin Young"s 29-year-old world record by eight hundredths of a second. read more He described it as a relief after months of speculation over who could topple the longest-standing record in men"s track. "You need to be at your a-level and to do all the right things, both in practice and in competition," he said. "It was really special." He has scarce time to savour that accomplishment, facing a field in Tokyo including American Rai Benjamin, Qatari Abderrahman Samba, who finished second and third behind him at the World Championships in 2019, respectively, and 21-year-old Brazilian Alison dos Santos, who won the Stockholm Diamond League meeting earlier this month. "The 400-metre hurdles is all of a sudden a very, very competitive race," said Warholm. "You always got to have your competitors in the back of your mind because they are there and they want my position." His chief rival, 23-year-old Benjamin poses perhaps the biggest threat, having nearly broken the 400m hurdles world record himself at the U.S. team trials last month, where he won the final in 46.83. read more Warholm said the event has undergone a "renaissance", including on the women"s side, with American Sydney McLaughlin breaking the women"s 400m hurdles world record at the June trials in her ongoing rivalry with Rio Olympic champion Dalilah Muhammad. read more "When you see other people perform well it motivates you somehow to do it as well," said Warholm. "You know you have to step it up when the other guys (are) bringing their A-game."