Vardy’s late goals in a 2-0 win at the Stadium of Light sent Claudio Ranieri’s side 10 points clear before second-placed Tottenham kicked off at White Hart Lane and judging by the way the Leicester fans reacted they have clearly started believing the impossible dream.
The visiting supporters, some of whom have already bought scarves embossed with “Premier League Champions”, gave a rousing rendition of “We’re going to win the league” at fulltime.
Tottenham, however, have proved durable pursuers while other more fancied sides have faltered and the way they turned over a lacklustre United suggests they still believe the season could have a final twist.
A flat first half at White Hart Lane, not helped by the score from Sunderland and United’s late arrival due to traffic jams forcing a 30-minute delay, was followed by a vibrant second period from Mauricio Pochettino’s team.
Three goals in six minutes from Dele Alli, Toby Alderweireld and Erik Lamela earned Tottenham a first home league win over United since 2001 — a result that meant Leicester are at least guaranteed a top-four finish and a place in the Champions League’s playoff round.
United, meanwhile, remained fifth, four points behind Manchester City, and their hopes of salvation this season are more likely to come in the FA Cup in which they face West Ham United in a quarter-final replay on Wednesday.
With five matches remaining Leicester have 72 points and Tottenham have 65 with Arsenal back in third on 59.
Liverpool moved into eighth place with a 4-1 home victory over Stoke City — the perfect warm-up for their Europa League quarter-final second leg against Borussia Dortmund on Thursday.
Leicester will be guaranteed an improbable first top flight title if they win three more matches after grinding past a poor Sunderland side who are sliding towards relegation.
Ranieri’s side have now won five matches in a row without conceding a goal and the Italian’s emotional reaction to victory suggests he finally believes the miracle may happen.
“The fans must continue to dream but we must stay focussed and concentrated, we have now two tough matches at home,” he said. “We have achieved nothing yet though. We must stay calm, stay strong and keep going.”
Vardy broke the deadlock in the 66th minute when experienced defender Younes Kaboul failed to deal with Danny Drinkwater’s long ball and the England striker guided his shot past goalkeeper Vito Mannone.
Jack Rodwell wasted a great chance to equalise for Sunderland, wafting a shot over with the goal gaping, and Vardy raced away to seal victory in stoppage time to take his tally in the league to 21.
He is the first Leicester player to score more than 20 goals in the top flight since Gary Lineker in 1984-85.
Only Tottenham’s Harry Kane has more this season, although the Spurs striker for once did not get on the scoresheet on Sunday. He did have a hand in Tottenham’s opener though, releasing Christian Eriksen on the left before the Dane crossed for Alli to finish easily past David De Gea.
Four minutes later Lamela, guilty of a terrible first-half miss, curled in a free kick for Alderweireld to meet with a textbook glancing header and with Spurs rampant Argentine Lamela then finished off a flowing move with precise shot.
United’s fans had taunted Tottenham with a chant of “You Nearly Won The League” during the first half, but hope had returned in north London by the time the final whistle blew.
“It was important for us to show character after Leicester’s game, because we were under pressure,” Pochettino told reporters. “It’s true we gave a message to them that we are there. We are waiting and fighting.”