League One Brentford served up the night's big upset and triggered scenes of jubilation in West London by knocking out Premier League Everton 4-3 on penalties after holding the visitors 1-1 in normal time.
GEAR:Order the new Arsenal home shirt here and save 10%, courtesy of Kitbag
With the score also 1-1 after the 90 minutes at White Hart Lane, French midfielder Nasri overcame his own superstition to shatter Spurs' hopes with two spot kicks in the space of three minutes early in extra-time.
"He had a superstition to think that when the penalty is made on you, not to take it," said Arsenal manager Arsene Wenger after his club's biggest win at White Hart Lane in 32 years.
"I tried to prove to him that it's only based on fear. It's gone tonight... he realises now it was a bad superstition."
"I thought the first one (penalty) was harsh," said Tottenham manager Harry Redknapp. "Really, I think he's dived. The second one was a blatant penalty."
Second division Burnley savoured the night's other upset with a 1-0 home win over their former manager Owen Coyle's Premier League Bolton Wanderers.
The match started after a minute's applause for former England international Bobby Smith, centre-forward in Tottenham's double-winning side of 1960/61, who died on Saturday aged 77.
Wenger, serving a one-match touchline ban for his behaviour at Sunderland on Saturday, watched from the directors' box and had to resort to texting instructions to the dugout.
