Their form has been criticised and confidence has plummeted worryingly but, just when it mattered most, Gianfranco Zola and Tore Andre Flo rose to the occasion to secure Chelsea's place in the quarter-finals of the Champions League.

Only against Gillingham in a 5-0 romp in the FA Cup have the increasingly beleagured figures of Zola and Flo found respite from their woes in front of goal since early January.

However, after Frank Leboeuf had seen a ninth-minute penalty saved - only his second miss in 20 attempts - the familiar grin finally reappeared on Zola's face as he volleyed home to put the Blues ahead six minutes before the break.

And even after substitute Bonaventure Kalou had levelled for the Dutch champions 14 minutes into the second half, Chelsea responded with authority.

Yet again Dennis Wise was their inspiration, capping another masterful captain's display in central midfield with a header to score for the third consecutive game as put the visitors back ahead.

Then it was Flo, who may have scored 13 goals before mid-January but has struggled since, who made the game safe with a sweetly-sstruck left-foot shot past keeper Jerzy Dudek.

Boss Gianluca Vialli may have had few other options to play with up front, but his faith in his European strikeforce was clearly rewarded.

Chelsea now welcome Lazio to Stamford Bridge in their final group game next week safe in the knowledge that they are already into the last eight by virtue of beating Feyenoord twice - and just a draw away from winning the group outright.

The scoreline in that first encounter with Feyenoord back in November was exactly the same yet the Dutch side, who were then divided by internal dissent, were a far more impressive scalp this time around.

After all, they had since beaten Lazio in Rome as well as drawing against the Italian team and defeating Marseille at home.

After a torrential downpour just before kick-off had eased, Chelsea - with Dan Petrescu slotting impressively back into defence as Albert Ferrer was injured, and with Roberto Di Matteo making his first European start of the campaign - threatened first.

Zola played a neat one-two with Gustavo Poyet only for the Italian's volley to be blocked by keeper Dudek, who also saved a low shot from Flo.

Composed at the back and commanding in central midfield, the Blues took the game to the home side and Wise used his vision to thread a superb pass through the Feyenoord defence for Flo to scamper onto.

Centre-back Kees Van Wonderen rushed across to challenge the Norwegian, who crumpled to the ground after the defender left his leg in and Danish referee Knud Erik Fisker duly awarded a penalty.

Leboeuf, normally such an assured penalty-taker whose only previous miss was against Blackburn last season, stepped up confidently enough but his shot was weakly struck straight along the ground at Dudek.

The Frenchman slammed his fist onto the turf in disgust with himself but after pausing to regroup, Chelsea soon reaffirmed their authority, with Marcel Desailly back to his imperious best at the heart of their defence.

The Blues also continued to create the clearest openings, with full-back Tomasz Rzasa clearing a header by Poyet off the line, while Wise's long-range effort was tipped over.

Petrescu then played a high ball forward and when Bert Konterman, challenged by Flo, could only half-clear it, Zola took one neat touch before striking a half-volley against the inside of one post before the ball rolled just inside the opposite upright.

It was only the Italian's fourth goal of the season in his 32nd starting appearance. He scored a late penalty against Gillingham, but before then was last on the mark against Galatasaray in the Champions League back in October.

Feyenoord sent on striker Kalou for midfielder Patrick Kauwe at the start of the second half and briefly came alive.

Three shots went over the bar, Julio Cruz was denied by a superb tackle by Leboeuf and then Celestine Babayaro survived a penalty appeal after tangling with Kalou.

However, the Feyenoord substitute, who has only recently recovered from injury, was soon back on his feet to convert a cross from the left flank by Rzasa on 59 minutes.

Keeper Ed de Goey, playing against his former club, failed to command his penalty area as he only got his fingertips to the cross, while Leboeuf also lost his man as Kalou swooped.

Chelsea were stung into renewed action though, with Didier Deschamps' powerful drive being tipped over while Rzasa was lying prone in the penalty area.

And they went back into the lead when captain Wise, who had scored against both Marseille and Everton in the past week, rose imperiously to meet Babayaro's cross from the left flank and power a header past Dudek on 63 minutes.

Just six minutes later, the Blues were 3-1 ahead and on the verge of the quarter-finals as Flo cut inside from the left flank, powered his way past Van Wonderen and struck a left-footed shot just inside the far post.

Flo shot over the bar in the final stages, while de Goey stretched to save a volley by Cruz, but Chelsea were safely into the quarter-finals with one of the most impressive European results in the club's history.

Teams:

Feyenoord: Dudek, Rzasa, Van Wonderen, Konterman, Van Gobbel, De Visser (Samardzic 75), Paauwe (Kalou 46), Van Gastel,Bosvelt, Tomasson, Cruz.

Subs Not Used: Graafland, Gyan, Van Vossen, Korneev, De Haan.

Booked: Bosvelt.

Goals: Kalou 59.

Chelsea: De Goey, Babayaro, Desailly, Leboeuf, Petrescu, Poyet (Morris 77), Wise, Deschamps, Di Matteo,Zola (Ambrosetti 90), Flo.

Subs Not Used: Cudicini, Hogh, Sutton, Thome, Harley.

Goals: Zola 39, Wise 64, Flo 69.

Att: 45,000

Ref: Knut-Erik Fisker (Denmark).