Leicester played out a 1-1 draw with United away from home at Old Trafford in the Premier League.
Anthony Martial drilled home a near-post finish from Antonio Valencia's cross to put the Red Devils in the lead after just eight minutes.
The Foxes equalised on 17 minutes through Wes Morgan, and ended the game with 10 men due to the sending-off of Danny Drinkwater for two bookable offences late on.
Former Leicester striker Lineker has taken to Twitter to give his reaction to the final result.
It's supposed to be enjoyable isn't it? Excruciating watch, but a massive point!— Gary Lineker (@GaryLineker) May 1, 2016
The result means that Premier League leaders Leicester are now eight points clear of Tottenham Hotspur, who are currently second in the standings and have a game in hand.
If Tottenham fail to pick up all three points against London rivals Chelsea at Stamford Bridge on Monday evening, then the Foxes will be crowed champions of England.
Ranieri has revealed that after the match on Sunday afternoon, United manager Louis van Gaal wished him and his players good luck.
The Italian tactician has also explained why he will not watch Monday evening’s Premier League game between Chelsea and Tottenham.
“I'd like to watch the Tottenham match but I'm on a flight back from Italy so I might not know the result until I land,” Ranieri told BBC Sport (16:19). “For us it's important to continue to work. I met Louis van Gaal in 1994 - he said to me good luck."