"The tennis players say 'the serve to win Wimbledon', the last match, is the most difficult," Guardiola told the BBC.
A match that started with Villa goalkeeper Emiliano Martinez conceding a shocking own-goal after 62 seconds turned into a great escape, and near-win, as Duran came on to save the night with strikes in the 85th and 88th minutes.
"I don't know where we should be when we had all the players on board, but definitely it is if there are players all on board, then you will get more points," said Ten Hag.
Manchester City still have the destiny of the title in their own hands as the defending champions have two matches left to Arsenal's one.
Mykhailo Mudryk also scored for Mauricio Pochettino's Chelsea, who are seventh in the table with two games remaining, fuellng their hopes in the race for a European spot next season
Pep Guardiola's men were dominant but had to wait until the hour to make the points safe when Phil Foden swept in his 25th goal of the season
If Arsenal fail to beat United, then City can wrap up an unprecedented fourth successive English title with a victory at Tottenham on Tuesday.
Manchester City hit the top of the Premier League with one week of the season remaining as two goals by Josko Gvardiol and one each for Phil Foden and Julian Alvarez sealed a 4-0 demolition of Fulham on Saturday.
Former United star Beckham was in Manchester on Thursday to attend the premiere of a new documentary about the club's 1999 treble-winning side.
"The referee is unbelievable and it's ridiculous. It is difficult to accept," Pochettino said.
The win took 15th-placed Everton to 36 points from 35 matches, 11 points ahead of 18th-placed Luton Town
The single point leaves Liverpool third in the table on 75 points, one behind defending champions Manchester City, who have two games in hand.
Phil Foden issued a warning to Manchester City's title rivals after the champions' "frightening" attack inspired a vital 4-0 demolition of Brighton.
Chelsea could be without top scorer Cole Palmer for Tuesday's clash away at Premier League leaders Arsenal with the forward struggling to recover from illness, manager Mauricio Pochettino said on Monday.
Tottenham Hotspur have suffered a setback in their pursuit of a top-four place in the Premier League as defender Destiny Udogie is out with injury for the rest of the season, the club confirmed on Sunday
“He [Palmer] was asking for two seasons to leave and I said stay. He said he wanted to leave. What could we do?” Goal.com quoted Guardiola.
Jurgen Klopp was headed for a glorious send-off in his final season at Liverpool just a few weeks ago, but talk of a potential quadruple is now long forgotten as the Reds have come off the rails.
"They like to play with the pressure. They like to know - dead or alive."
Arsenal's Premier League title hopes suffered a massive blow as Aston Villa struck twice in the closing stages to boost their top four bid with a dramatic 2-0 win at the Emirates Stadium on Sunday.