Nicolas Anelka proved why Chelsea recently paid £15million for his services by scoring his first goal for the FA Cup holders to steer the Blues into the last 16 of this year's competition.

Anelka's predatory instincts came to the fore in the 51st minute of a mediocre fourth-round tie, before he then set up Shaun Wright-Phillips for the game-killing second goal eight minutes from time.

Wigan substitute Antoine Sibierski did score a stunning strike in the 87th minute, before Marcus Bent almost forced an unlikely replay when he rattled the crossbar in injury-time.

But in the end it was a comfortable night's work for Chelsea, whose current unbeaten run stretches to 10 matches - despite the fact they continue to be without an array of stars.

Frank Lampard, John Terry, Michael Ballack and Andriy Shevchenko are all out through injury, while Mikel Jon Obi, Didier Drogba, Salomon Kalou and Michael Essien are on African Nations Cup duty.

With Ashley Cole also absent, it is a case of continuing to mend and make do for boss Avram Grant.

But Chelsea continue to find a way to win, even if the opening 45 minutes were disjointed by their standards as defences dominated - neither Chris Kirkland nor Petr Cech made any kind of meaningful save in the first half.

The visitors started brightly and after just 50 seconds Chelsea swiftly ripped through the Latics, culminating in Steve Sidwell sliding the ball on for Joe Cole, making his 200th appearance for the club.

But the man who despatched a clinical shot to see off Everton in midweek was this time wide with a curled right-foot shot from the edge of the area.

After that, Wigan tightened up considerably in defence, with their only other moment of consternation in the opening period arriving in the 11th minute.

When Kevin Kilbane collided with Nicolas Anelka in the area there were Chelsea appeals for a penalty, but referee Uriah Rennie chose to dismiss the protests.

Contact, though, was made - although Anelka arguably went to ground too easily.

A scrappy affair followed, not helped by the rutted JJB Stadium pitch which has given Wigan manager Steve Bruce recent cause for concern.

That, combined with Chelsea's tight back-four, offered the Latics precious few moments to savour in and around the visiting area.

There was one pass from Emile Heskey played into the path of Bent, but with only Cech to beat, Wayne Bridge produced a perfectly-timed tackle to thwart the danger.

That was it as far as the first half went, so mercifully for all concerned the second half did not follow a similar pattern, with the goal the game needed arriving six minutes after the restart.

After Ryan Taylor had been robbed of the ball inside the centre circle, Chelsea broke to devastating effect, culminating in Juliano Belletti's pass into the heart of the area.

With Titus Bramble just playing Anelka onside, the Frenchman beat the advancing Kirkland to the ball to stab home from 12 yards for his 12th goal of the season overall.

Wigan, though, could have drawn level three minutes later, only for the legs of Cech to deny Heskey's effort from the corner of the six-yard box.

Following that came a moment of controversy that had the entire Chelsea bench jumping off their feet and into the technical area in protest.

Off the ball, Michael Brown caught Chelsea captain Claude Makelele in the throat with an elbow, yet neither Rennie nor his assistant saw the incident.

Bruce was far from happy with Chelsea's enraged stance, yet it may be one for the Football Association's technical department to deal with as no booking was issued.

Chelsea then clinched their place in the fifth round in the 82nd minute, initially after left-back Kilbane lost a 50-50 challenge with Anelka in the right-back position.

Anelka ran on towards the area and slipped a ball across the 18-yard box for Wright-Phillips to sidefoot home off the legs of Kirkland for his sixth goal of the season.

Chelsea should then have seen the game out, but first came Sibierski's immaculate volley in off the underside of the bar, prior to Blues' hearts pounding with Bent's effort.

But Grant's side, though, continue to march on in all four competitions.

Teams:

Wigan Kirkland, Melchiot, Bramble, Scharner, Kilbane, Valencia, Brown, Palacios (Sibierski 77), Taylor (Koumas 58), Bent, Heskey (Aghahowa 85).

Subs Not Used: Pollitt, Boyce.

Booked: Bramble, Scharner, Palacios, Aghahowa.

Goals: Sibierski 87.

Chelsea Cech, Belletti, Carvalho, Alex, Bridge, Malouda (Ferreira 80), Makelele, Sidwell, Wright-Phillips, Joe Cole, Anelka (Pizarro 90).

Subs Not Used: Cudicini, Sinclair, Ben-Haim.

Booked: Alex, Carvalho.

Goals: Anelka 53, Wright-Phillips 82.

Att: 14,166

Ref: Uriah Rennie (S Yorkshire).