Spurs head to Bolton on Tuesday currently in possession of the last Champions League place, but face a side just as desperate for points in their fight to stay in the top flight.
Redknapp - overlooked by the Football Association for the England job this week - knows full well what to expect at the Reebok Stadium on Tuesday.
"Bolton away is always tough," he said.
"We've been there enough times over the years and it's always a difficult place to go.
"They are playing well, Owen (Coyle, manager) has got them going at the moment.
"It will be a hard game but we've got to go there and be positive."
Redknapp is not taking fourth place for granted - in fact, he is as prepared for his side dropping down to fifth as the Spurs boss is for pipping north London rivals Arsenal to third.
"You can't predict results," he told Spurs TV.
"Manchester United had an eight-point lead after (Manchester) City got beat at Arsenal, you thought that was the end of them, you thought it was all over. You just can't tell.
"You look at Wigan's games and they had no chance (of survival). They had to go to Liverpool, Chelsea, Arsenal, play United, Newcastle, five of the top six, and they go on this incredible run. You just can't predict results.
"You never know. You just have to keep going. That's all we can do. We've two tough away games this week and then a tough home game against Fulham to finish with. That's three hard games.
"Newcastle have three tough games, for sure. Chelsea might have the best fixtures.
"We have to keep going and if we play well, we can do it (third)."
Spurs go into the match in decent spirits having beaten Blackburn 2-0 in a strong showing on Sunday.
They went into that match with a record of just one win in nine matches, but Redknapp insists that was a false representation of Spurs' performances.
"We're fine. As I said all along, we haven't been playing badly," he added.
"We had one bad performance against Norwich, they played well and we had a bad day. Other than that we've played very well, the results just weren't going our way.
"We beat Swansea, beat Bolton in the FA Cup, drew at Sunderland, beat Blackburn well at home, so we've not been in bad form, we're confident we're playing well."