Mount hit the post in the shootout as Chelsea were eliminated by Spurs from the Carabao Cup as Jose Mourinho’s side advanced to face Stoke City in the next round.
Chelsea had led 1-0 through a goal from Timo Werner before a late Erik Lamela strike forced a shootout, which Spurs won.
Mount came in for some heavy criticism after missing the spot kick. Former Chelsea defender Frank Leboeuf described his performance as ‘awful’.
‘Mason Mount was awful all game,’ said Leboeuf.
‘He’s a very talented player but some players have to wake up if they want to have a career.’
But Lampard revealed that those within the Chelsea camp have been nothing but supportive of the midfielder – who looked gutted after the match – after his disappointing penalty miss.
‘Everybody rallied around Mason as they would do around anyone in the squad,’ said Lampard ahead of Chelsea’s Premier League clash with Crystal Palace.
‘He will play many games of high importance and he has our full support.’