Mikhail Tal's chronic kidney problems contributed to his defeat in his 1961 return match with Botvinnik, and his doctors in Riga advised that he should postpone the match for health reasons. Averbakh claimed that Botvinnik would agree to a postponement only if Tal was certified unfit by "Moscow" doctors, and that Tal then decided to play. The 1961 world championship lasted 21 games and Botvinnik won ten of them, for a total score of +10−5=6, reclaiming the title he had lost a year earlier and becoming the oldest winner of a world championship match at 50.