The Denmark international connected with a deflection off United defender Chris Smalling and curled home his shot from seven yards out to quickly open the scoring on Wednesday — marking the fastest goal the Red Devils have conceded in the Premier League.
Ledley King's goal after 9.5 seconds for Tottenham against Bradford City in 2000 remains the swiftest strike in league history, however.
And the former England international took to Twitter to celebrate his record surviving Eriksen's effort, writing "AND STILL......."
AND STILL....... pic.twitter.com/0sc2OyJDkx— Ledley King (@LedleyKing) January 31, 2018
It was, however, the fastest goal scored in the Premier League since Opta began keeping track during the 2006-07 season, besting a trio of 13-second strikes that all occurred in 2013: Manchester City's Jesus Navas against Spurs, Southampton's Jay Rodriguez against Chelsea and Stoke City goalkeeper Asmir Begovic's wind-assisted effort against Saints.
Eriksen now has seven goals in 25 Premier League appearances this season for Spurs, who doubled their advantage over United on Wednesday through a 28th-minute Phil Jones own goal and held on for the 2-0 win.
The opener was the first goal Jose Mourinho's men have conceded in their last six games.
The goal was also the 50th Eriksen has scored for Spurs since his move to north London from Ajax in the summer of 2013.
During that time, only Harry Kane has netted more goals for Spurs, with the England international scoring 128 times for the club prior to kick-off against United.
Spurs now sit fifth in the Premier League, two points out of the top four and five points back of second-placed United.