Kevin Phillips continued his remarkable goalscoring form for West Brom as his second-half penalty helped seal a comfortable FA Cup fourth round win at Peterborough.

Phillips only entered the fray at half-time but smashed in his 17th goal of the season from the spot after referee Jonathan Moss harshly sent-off defender Craig Morgan.

Early goals from Roman Bednar and Robert Koren had given the Championship side a half-time lead but Darren Ferguson's side were still in contention until Phillips' third.

The League Two high-fliers showed plenty of promise and were twice denied by goalline clearances but the quality in possession of Albion proved decisive as they ruthlessly punished some slack defending.

Ferguson's Peterborough started brightly and saw a deflected Aaron Mclean strike cleared off the line by James Morrison after a vicious inswinging corner from Dean Keates.

The pace up front of Aaron McLean and Craig Mackail-Smith, who have scored 38 goals between them this season, was causing problems but it was the Championship leaders who grabbed the lead with their first attack of substance in the eighth minute.

Filipe Teixeira received possession with his back to goal and cleverly flicked the ball over Jamie Day's head.

Craig Beattie collected the ball and fired a shot across goal where Bednar was on hand to slam into the roof of the net from inside the six-yard box.

The goal dampened the feverish atmosphere inside a packed London Road and Mowbray's side further extinguished any hopes of an upset with a second in the 14th minute.

A long ball out of defence was superbly brought down on the chest by Beattie on the halfway line before he span and released Morrison who was breaking clear down the right.

The former Middlesbrough winger outpaced Day before firing in a low drive from the edge of the area.

Peterborough goalkeeper and record signing Joe Lewis did brilliantly to tip the shot onto the inside of the post but after Beattie had fluffed his attempt from the rebound Koren swept home from 12 yards.

The home side had claims for a penalty waved away by Moss when Mackail-Smith's header appeared to strike Bostjan Cesar's arm and then saw Morrison again deny them a goal when he hacked away Morgan's volley from another Keates corner.

Bednar was withdrawn at the break to be replaced by Phillips but it was the home side who had the first chance of the half.

Persistence down the right earned Chris Whelpdale a crossing opportunity and his ball in was turned on by George Boyd to Mclean.

The prolific forward showed excellent technique to rifle in a rising drive on the spin but Dean Kiely was alert to palm his shot away.

It was a terrific stop by the veteran and Phillips put the result beyond doubt in the 57th minute.

A slack header by Kieran Charnock was turned back towards goal by Morrison and Beattie cleverly flicked the ball on to release captain Jonathan Greening into the area.

Greening took a touch but was denied a shooting opportunity as Morgan tripped him and referee Moss had no hesitation in awarding the penalty and sending the Wales international off.

Phillips hammered the ball low into the bottom left corner to reserve Albion's spot in the fifth-round draw.

Keates did draw another decent save from Kiely with a powerful header from a Whelpdale cross but Beattie should have made it four at the other end after a fluid counter-attack but headed wastefully over.

Teams:

Peterborough Lewis, Newton, Morgan, Charnock, Day, Whelpdale, Keates (Mitchell 76), Lee, Boyd, Mackail-Smith, Mclean.

Subs Not Used: McKeown, Crow, Gnakpa, Blanchett.

Sent Off: Morgan (57).

Booked: Lee.

West Brom Kiely, Hoefkens, Albrechtsen, Cesar, Robinson, Morrison, Koren, Greening (Brunt 64), Filipe Teixeira, Bednar (Phillips 46), Beattie (MacDonald 78).

Subs Not Used: Steele, Barnett.

Booked: Hoefkens, Beattie.

Goals: Bednar 7, Koren 15, Phillips 58 pen.

Att: 12,701

Ref: Jon Moss (W Yorkshire).