Bolton missed the chance to go fourth as they were held by Southampton.
Sam Allardyce's side looked on course to move into the Champions League places after Stelios Giannakopoulos gave them the lead after 25 minutes.
He headed home from El-Hadji Diouf's cross as Bolton laid siege to the Southampton goal, with Nigel Quashie twice clearing off the line.
But Southampton rallied and grabbed a crucial point after 69 minutes when Kevin Phillips scored from close range.
Bolton restored Diouf to their starting line-up, and he was instrumental in a first 45 minutes dominated by the team chasing a place in Europe.
Bruno N'Gotty headed over when unmarked, and Southampton somehow survived an 18th minute goalmouth scramble that saw Quashie clear off the line from Kevin Nolan and Giannakopoulos.
Fernando Hierro's shot was deflected inches wide before Bolton deservedly took the lead after 25 minutes.
Diouf did brilliantly to send in a cross from the right flank, and Giannakopoulos stole in to send a powerful header past Antti Niemi.
Bolton continued to pour forward and Diouf and Jay-Jay Okocha both had shots saved by Niemi.
The pattern continued after the interval, and Bolton should have doubled their advantage seconds after the break.
Giannakopoulos' cross was met by the unmarked Speed, whose point-blank header was somehow blocked by Niemi.
The rebound fell perfectly for Diouf, but he fired well over the top with the goal at his mercy.
Southampton had sent Matt Oakley for Graeme Le Saux at half-time, and it had a dramatic effect on Redknapp's strugglers.
Jussi Jaaskelainen had been a virtual spectator, but he produced a stunning double save to keep Bolton in front after 56 minutes.
Rory Delap's cross was headed down by Crouch, but Jaaskelainen made a fine reflex save before recovering to block the rebound from Oakley - who was then well off target.
Southampton were a team transfomed, and Phillips put them level after 69 minutes.
Delap's long ball was missed by N'Gotty and Phillips pounced to beat Jaaskelainen from 10 yards.
Bolton sent on striker Davies for Nolan, and he almost made an instant impact, hitting the post from Okocha's shot.
Okocha then shot into the side-netting before glancing a 20-yard free-kick off an upright.
Bolton were in the ascendancy again, and it took a miraculous save from Niemi to deny Davies from eight yards in the dying moments.
Bolton boss Sam Allardyce
"We had more chances in this game than in any other game since I came to this club four years ago.
"We are disappointed not to win, but we are not disappointed with the performance or the support we got.
"I was worried the chances Gary Speed and El-Hadji Diouf missed at the start of the second half might cost us, and sadly they did.
"It was a combination of good defending, good goalkeeping and bad finishing. We are still in the hunt for fourth place and it is not over yet.
"A couple of seasons ago a point at home against Southampton would have been regarded as good - that we are disappointed shows the progress we have made."
Southampton boss Harry Redknapp
"The players dug in well for us because we were all desperately disappointed to lose the way we did to Aston Villa after playing well enough to be five or six up.
"We should be long gone from this relegation battle because we've only had two bad performances since I came here, but we are still in at and I was happy with what I saw from the players.
"I told the players we had to believe in ourselves in the second-half and it was a different game after that.
"People criticise Bolton's style, but they played some great stuff, some of the best football we've had played against us this season."
Bolton: Jaaskelainen, Hunt, N'Gotty, Ben Haim, Candela (Gardner 87), Hierro, Nolan (Davies 65), Okocha, Speed, Giannakopoulos (Jaidi 90), Diouf.
Subs Not Used: Poole, Campo.
Booked: Ben Haim, Giannakopoulos.
Goals: Giannakopoulos 25.
Southampton: Niemi, Delap, Lundekvam, Jakobsson, Le Saux (Oakley 45), Telfer, Quashie, Anders Svensson (Nilsson 80), Higginbotham, Crouch, Phillips.
Subs Not Used: Smith, Camara, Davenport.
Goals: Phillips 69.
Ref: M Clattenburg (Co Durham).