Defeat for Villa would leave them five points adrift of Tottenham in fourth and seriously hamper their push for a place in the Champions League next season.
Villa, boosted by the return of striker John Carew after a four-match absence with a knee injury, are hoping to pull off a second successive win in the capital following their impressive 2-0 victory at Fulham last week.
O'Neill: Knows the game at White Hart Lane is crucial
O'Neill said: 'The Tottenham game is a big, big game for us.
'Tottenham have been going great. They have some real quality players and have got strength in depth, which perhaps they may have lacked a couple of years ago.
'It augurs well for them as they played very well in the FA Cup replay up at Leeds and they will be ready for our match. They are a very fine side as they proved here at Villa Park not so long ago.
'It is up to us but I think we are a fine side ourselves. The results we have had recently may not completely have reflected the manner in which we have played.
'I'm thinking in particular about the games we had against Liverpool and West Ham when we might easily have had four points and finished with one.
At the double: Gabriel Agbonlahor scored twice for Villa tat Fulham last weekend
'We were back on track again against Fulham. That was a difficult game for us to negotiate and it is up to us do the same on Saturday against Tottenham.'
Villa have not scored as many goals as O'Neill would have hoped at times thisseason and he added: 'Much was made of us not scoring of course and it is going to be highlighted. That is the nature of the business.
'The irony was that we were scoring goals galore in FA Cup matches and League Cup semi-finals.
'Purely from a league point of view it was great to win 2-0 at Craven Cottage with two great goals from Gabby Agbonlahor and he is now off and running again.
'We are now getting to a stage of the season when it is important to keep the scoreboard ticking along and whatever points we pick up will be vital.
Score draw: Michael Dawson celebrates his equaliser for Spurs at Villa Park in November
'Our next two games could not be more difficult, away to Tottenham and at home on Wednesday to Manchester United, sides who are going for everything themselves.
'I suppose we consider ourselves in that pack and that is, I think, is a great testament to the efforts of the team this season.'
O'Neill knows Villa will have to stop in-form striker Jermain Defoe and he said: 'Defoe is playing exceptionally well.
'He is a proper goalscorer but don't forget Peter Crouch, a player Aston Villa had in their ranks not so long ago, who is also is a top quality player.
'I think the combination of the two of them has always been difficult as they are two very talented players.'
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