Pittsburgh beat Washington in the NFL for a dominant victory that US presidential candidate Barack Obama will see as a good omen.
For all but one of the last 17 presidential ballots, since 1937, a Redskins victory has signalled a win for the party currently in power.
Pittsburgh held Redskins runner Clinton Portis and sacked quarterback Jason Campbell seven times for a 23-6 win.
Obama was pictured last week at a rally with a Steelers jersey bearing his name, given to him by team owner Dan Rooney.
His Republican rival McCain, from Arizona, has had the backing of former Redskins coach Joe Gibbs.
There was a caveat in 2004, when a Green Bay win should have signalled defeat for George W Bush, but some rule-backers note that Bush lost the popular vote in 2000, so his re-election was not a true repeat.