Dean Wilkins will be feeling even more sick after a defeat which plunges his side deep into relegation trouble.

The Albion manager missed the match with flu and striker Alex Revell was also ruled out by illness.

The Seagulls slumped to a sixth straight defeat in their absence, Darren Byfield scoring the only goal of the game in the first half.

The Lions held on for their first clean sheet in League One this season to close the gap between them and the Seagulls towards the foot of the table to one point with a game in hand.

Albion are giving away goals at one end - Byfield's was another example - and they have failed to score now in their last three matches, which is a recipe for relegation.

There were five changes to the Albion team knocked out of the FA Cup at West Ham, three of them enforced.

Sam Rents returned at leftback and Richard Carpenter to the centre of midfield in place of the suspended Kerry Mayo and Dean Hammond.

Joe Gatting took over up front from Revell. Dean Cox, available again after a one-match ban, resumed on the left at the expense of Alex Frutos and Gary Hart was preferred on the right to Tommy Fraser.

Carpenter, Hart and Guy Butters, deputising as captain for Hammond, provided the kind of experience the Seagulls are pursuing to strengthen a young squad before the close of the January transfer window.

Millwall, beaten at Stoke in the FA Cup, brought in Tony Craig for Marvin Williams and Neil Harris replaced Poul Hubertz in attack on his return to the club from Nottingham Forest.

The match had the smell of a relegation scrap from the outset on a horribly wet and windy afternoon but there were occasional flashes of quality in the first half.

Jake Robinson was not expected to start for Albion after his goal drought continued in the Reserves at Whitehawk during the week but Revell's absence gave him a reprieve.

He looked eager to make the most of it in a lively opening when Cox picked out his run with a typically astute pass.

Robinson cut inside and his swerving shot was beaten away for a corner by Millwall keeper Lenny Pidgeley with a degree of discomfort at his near post.

Harris also showed a touch of class out of keeping with the occasion for the visitors with a clever backheel which released Chris Hackett in behind the Albion defence.

Hackett's low cross had danger written all over it and Joe O'Cearuill, making his home debut, did well to clear the ball over his own crossbar.

The 19-year-old on loan from Arsenal might easily instead have put through his own net.

The dreadful manner in which Albion fell behind midway through the first half epitomised their failure to keep a clean sheet at home in the League since the opening game of the season at Withdean against Gillingham back in August.

Paul Robinson, the Millwall captain and central defender, hit a long ball from deep inside his own half through the inside right channel, more in hope than expectation.

It should have been dealt with comfortably but it cleared the head of Joel Lynch, caught the wrong side of Byfield.

It left Byfield in the clear and Wayne Henderson hesitated before advancing off his line, with fatal consequences.

The Millwall marksman's clinical lob into the vacant net raised his tally for the season to eight, including a hat-trick in the Lions' last home game against his old club Gillingham.

Albion spent the rest of the opening 45 minutes foraging forward in the hunt for an equaliser.

They forced a flurry of corners and Adam El-Abd somehow managed to drag a shot from a tight angle so far off target that it went for a throw-in when he was well placed from Gatting's pass across the face of goal.

It was another case of what might have been for the Seagulls in first half stoppage time. Danny Senda, fresh from signing a contract extension for Millwall, miscontrolled a high ball inside his own box, leaving Cox in the clear, but he could only find the side netting.

From the moment they went in front Millwall were content to get men behind the ball and rely on the zest of Byfield on the break.

Although Albion dominated the possession they found the visitors hard to break down.

O'Cearuill, getting forward from rightback much more than he was able to at West Ham, was one of the Seagulls' more eyecatching performers.

He exchanged passes with Robinson before going down inside the box but there was no contact worthy of a penalty and Richard Shaw, Millwall's experienced defender, pointed an accusing finger, claiming O'Cearuill had dived.

The Seagulls, for all their territorial supremacy, could not fashion many opportunities.

Robinson went close in the 63rd minute with a well-struck effort from 35 yards which flashed just wide.

Wilkins' No. 2 Dean White and coach Ian Chapman threw on Nathan Elder for his debut and Fraser in place of Gatting and Carpenter with 17 minutes left.

The double substitution almost did the trick in the 81st minute when the powerful Elder met Fraser's teasing cross with a downward header at the far post which forced Pidgeley into a fine stop, scrambling away to his right.

With that went Albion's last chance of salvation and the frustration showed in the closing moments with bookings for Fraser and Cox.

As if Wilkins does not have enough problems, Fraser and Revell are now one more yellow card away from a suspension.