Blatter, 79, faces a criminal investigation over the payment, made nine years after Platini, 60, carried out consultation work for the Swiss.
Both men deny any wrongdoing.
“It was a contract I had with Michel Platini, a gentleman’s agreement that was followed through on,” Blatter told Swiss broadcaster RROTV.
Football’s world governing body Fifa has imposed a 90-day suspensionon Blatter and Platini while corruption claims concerning the payment are investigated.
Former France international captain and coach Platini says the money was an unpaid additional salary due from the time he served as Blatter’s advisor between 1998 and 2002.
Following a Uefa meeting on Thursday, the Football Associationsuspended its support for Platini’s bid to become Fifa president “until the legal process has been concluded and the position is clear”.
Uefa issued a statement saying Platini should be given the opportunity “to clear his name” and urged the Fifa ethics committee to conclude its investigation by mid-November.
The Fifa presidential election is scheduled to take place on 26 February 2016.
Meanwhile, Germany’s Football Association [DFB] announced on Friday it would investigate a €6.7m (£5m) payment to Fifa from the country’s 2006 World Cup organising committee.
Germany, whose bid was led by former World Cup-winning captain and coach Franz Beckenbauer, edged out favourites South Africa in the July 2000 vote to win the hosting rights for the 2006 tournament.
The DFB said it had found no indication of wrongdoing in the overall bid process, but questioned an April 2005 payment to Fifa “that may potentially not have been used for the intended purpose”.