Here, PA Sport's Ben Rumsby takes a look at both clubs.

MANAGERS

Tony Mowbray became one of the most sought-after young managers in the country after doing a superb job in his first job at Hibernian. The former defender turned them into a real force in the Scottish Premier League and he was West Brom's first choice as replacement for Bryan Robson following the latter's sacking 18 months ago. He led them to the Coca-Cola Championship play-offs at the first attempt but suffered Wembley heartbreak in the final. Promotion is the main objective this season but despite appearing the strongest side in the division, the Baggies have flattered to deceive.

Harry Redknapp's stock has surely never been higher. Not once, but twice the veteran boss has transformed Portsmouth into a genuine force in the Barclays Premier League. He was arguably the leading English candidate to replace Steve McClaren as national team boss, while he rejected a lucrative offer to take over at Newcastle before Kevin Keegan's return. Yet, his distinguished CV is missing a major honour, and he will never have a better chance to put that right.

SQUAD

West Brom boast the most talented squad outside the top flight, though it as emerged as one where the balance between attack and defence is too heavily weighted towards the former. The likes of Kevin Phillips, Roman Bednar, Zoltan Gera and Filipe Teixeira are arguably good enough to flourish in the Premier League but the Baggies appear to require major surgery at the back if they do manage to secure promotion.

Portsmouth's success this season is built on one of the most powerful squads in the country. Harry Redknapp's men are never outmuscled and there is enough pace throughout the side to cause any team problems. Redknapp has also managed to get the best out of veterans discarded by so-called bigger clubs, maintaining the eye for a bargain that is the hallmark of his management style.

FORM

Like virtually every team in the Championship, West Brom have been infuriatingly inconsistent this season. They were recently beaten 4-1 at home by struggling Leicester and almost suffered an even more shocking defeat against rock-bottom Colchester before netting twice in stoppage-time to win 4-3. Their last outing against Cardiff was a rare goalless draw but they remain the class act of the division and will go top if they win their game in hand.

Portsmouth are arguably in their best form of the season, having won four of their last five games in all competitions. That included a remarkable FA Cup quarter-final win at Manchester United, while Saturday's 2-0 win over Wigan has put them back in the frame for fifth place in the Premier League.

CUP PEDIGREE

West Brom win hands down when it comes to cup pedigree having won the competition five times compared to Portsmouth's one, although the most recent was 1968. Portsmouth won the FA Cup for the only time in their history in 1939, although they kept the trophy for seven years due to the Second World War.