(Reuters) - Former Soviet gymnast Larisa Latynina, for the last 48 years the biggest Olympics medals winner with a haul of 18, said on Wednesday she was happy to see U.S. swimmer Michael Phelps go one better and dubbed him "the world's greatest Olympian".

Phelps has won 19 Olympic medals, 15 of them gold, after taking a gold and silver in the London pool on Tuesday.

"I think that keeping the Olympic world record for 48 years is long enough," the Ukraine-born Latynina told Reuters by e-mail from London where she is attending the Games as a guest of the International Gymnastics Federation.

"I'm very pleased that a new, very talented Olympian has appeared and finally broke my record," said the 77-year-old, who competed in three Olympics at Melbourne (1956), Rome (1960) and Tokyo (1964). Her 18 medals included nine gold.

"Michael is now the world's greatest Olympian," she said of Phelps, who she met earlier this year.

"By the way, I'm very thankful to Michael because thanks to him, I again have become quite famous for the past 12 months. I wish he will keep the record for many decades to come."

(Reporting by Gennady Fyodorov in Moscow; editing by Jason Neely)