Arsenal are now favourites to claim third place in the Barclays Premier League despite Emmanuel Adebayor's penalty cancelling out Villa midfielder Chris Herd's deflected opener.
Spurs also had defender Danny Rose sent off early in the second period for a challenge on Villa defender Alan Hutton.
In contrast, the point for Villa virtually guaranteed another season of top flight football.
Redknapp said: "When you are down to 10 men and you are one-nil down it's a point gained in the end, but on the balance of the game it was two points lost.
"Of course, there was frustration because a win and we were guaranteed fourth place but it's all to play for still. There's one game left and look at the permutations.
"It could be Chelsea, it could be us, it could be Arsenal, it could be Newcastle. It's just impossible to tell.
"We've all got tough games next week. No one has got an easy game so it will be an interesting last game of the season."
Redknapp added: "Fulham next week will be a hard game. Mind you, Arsenal have got no gimme with West Brom away. Newcastle go to Everton.
"If Chelsea go and win at Liverpool and beat Blackburn, we'll have to win.
"A draw won't do. We need to win. But it will be a tough game. Martin Jol won't be coming back to Tottenham wanting to help us, that's for sure, and Fulham are a decent team."
Redknapp admitted that Rose probably deserved to be red carded.
He said: "It didn't look a great tackle, to be honest. I've just looked at it again. He caught Alan Hutton, there's no doubt about that.
"I don't know if he got pushed by Charles N'Zogbia and it's not like Danny. He's not a nasty player, it's not in his nature to do something like that, so it was a bit out of character."
Villa boss Alex McLeish insists he expects to remain in charge of the midlands club for next season despite the negative reaction of some supporters.
Chants of 'Sack McLeish' greeted the Scot from some fans on the final whistle.
McLeish admits it is has been a difficult season but is adamant he retains the support of club owner Randy Lerner.
He said: "It is as tough a season as I've had. I knew it was going to be a challenge but I've always stood up in the face of adversity.
"I assessed the squad at the start of the season and knew there was a possibility of being in the lower half of the table if we got injuries.
"Randy Lerner has been very supportive, he's sent positive texts in the last few days and there is no indication of an urgent meeting being required.
"I expect to be here next season and hope to win the fans over. In general, the fans have been excellent.
"I bought into the project here with Randy and the board and the need to reduce the wage bill.
"There has been some pain along the way but I have shown leadership and stood up in times of adversity."
McLeish opted to select midfielder Chris Herd despite fining him for his part in a nightclub incident.
He said: "I contemplated leaving Herd out after the incident. That was a big dilemma for me over the last 48 hours and did not sit comfortably with me.
"I did not want to cut off my nose to spite my face, he put in a good performance and hopefully will not behave like that again."
McLeish confirmed striker Andreas Weimann will be out of action for six weeks with a medial ligament injury.