Bolton were left frustrated as they were held by Marseille when they went in search of a place in the last 16 of the Uefa Cup at the Reebok Stadium.
Bolton were frustrated in their quest for a first-leg home win
Sam Allardyce's side suffered a first-leg stalemate and face an uphill task in the return game in France.
Bolton were denied a clear first-half penalty when Frederic Dehu handled Jay-Jay Okocha's 37th-minute cross.
But Jussi Jaaskelainen was Bolton's hero, diving bravely at the feet of Mamadou Niang after the break.
Okocha was back in Bolton's starting line-up after returning from the African Cup of Nations - but El-Hadji Diouf was out with a groin injury.
And Okocha produced the first moment of danger after six minutes, with a trademark long-range drive which was punched to safety by Marseille's former Manchester United goalkeeper Fabien Barthez.
Jaaskelainen needed to be alert as Marseille threatened on the break, and he was twice forced into saves by Taye Taiwo.
Niang's pace was a constant threat, but his shooting was wayward and he was off target on several occasions.
The most contentious moment of a closely-fought first half came after 37 minutes, when Bolton were denied a clear penalty.
Dehu used his hand to claw away Okocha's cross from Jared Borgetti, but Portuguese referee Olegario Benquerenca ignored the offence, despite having a clear view.
And Bolton almost felt the full force of the injustice after 49 minutes when Niang escaped from Bruno N'Gotty after a mistake by Okocha, but Jaaskelainen timed his dived at the Marseille striker's feet to perfection.
Bolton saw another penalty appeal ignored on the hour when Stelios Giannakopoulos fell under challenge from Lorik Cana, but again the referee waved play on.
Ricardo vaz Te replaced Borgetti after 66 minutes, and he almost had an instant impact with a close-range effort which was blocked by Barthez.
Jaaskelainen had been faultless when Marseille threatened, and once again he showed good handling from Franck Ribery.
Stelios wasted Bolton's best opportunity in the closing seconds, when he headed Ricardo Gardner's cross wide from six yards.
Bolton: Jaaskelainen, O'Brien, Ben Haim, N'Gotty, Gardner, Nolan, Faye, Okocha (Speed 60), Davies, Borgetti (Vaz Te 67), Giannakopoulos. Subs Not Used: Walker, Hunt, Jaidi, Perez, Fojut.
Marseille: Barthez, Ferreira, Beye, Dehu, Cesar, Taiwo, Nasri (Gimenez 73), Cana, Oruma, Ribery, Niang (Cantareil 90). Subs Not Used: Carrasso, Delfim, Meite, Civelli, Deruda.
Booked: Oruma, Cana, Cesar, Barthez, Ferreira.
Ref: Olegario Benquerenca (Portugal).