Sam Allardyce's departure from Newcastle has sent shockwaves through the Premier League and in particular at Portsmouth, whose manager Harry Redknapp was quickly identified as the number one choice to take over at St James' Park. The news put Portsmouth on the drift in a host of betting markets, from this weekend's game at Sunderland to their overall performance this season. The temptation for many punters will be to jump on the bandwagon and try to exploit the turbulence swirling around Portsmouth, but in football betting it usually pays to take a more long-term view and the Sunderland v Portsmouth match is a good case in point. Sunderland are third-bottom in the Premier League, with half the points accumulated by eighth-placed Portsmouth, and backing them to win based on no more than the uncertainty at Portsmouth makes little sense. Portsmouth have lost only five games out of 21 in the Premier League this season and three of those were against members of the big four. The defeats by Arsenal, Chelsea and Liverpool are the only road losses suffered by Portsmouth and, whatever else has changed at Portsmouth, with key midfielders Sulley Muntari, Papa Bouba Diop and John Utaka called up for the African Cup of Nations, one thing that hasn't altered is their defence. The chief difference for Portsmouth in Redknapp's second spell at the club is that he sacrificed some of his attacking principles to build a stronger back line, and the combination of Sol Campbell and Sylvain Distin in the heart of defence has proved a masterstroke. That is what has made Portsmouth so difficult to beat this season and, outside the big four, only West Ham have conceded fewer than Portsmouth's 20 goals, which works out at just under one goal conceded per game. While Redknapp deserves great credit for his success at Portsmouth this time around, it is surely no coincidence that the defensive improvement has come with former Arsenal and England defender Tony Adams on Redknapp's backroom staff. Those strong foundations are not going to collapse overnight and Portsmouth have an excellent chance at Sunderland tomorrow night. In all games against the current bottom eight teams, Portsmouth have won six and lost only once, at home to Middlesbrough last month. Sunderland, meanwhile, have taken only one point from a possible 33 in games against current top-half teams and are coming off a humiliating 3-0 home FA Cup defeat by Wigan. They have lost three out of four at home to top-half teams, with one draw, and the highest-placed team they have beaten at the Stadium of Light this season were Tottenham back on the opening day of the season. On form, Portsmouth should avoid defeat at least, especially with their strong defence, and they are good value on the handicap. Form and value should always be the chief considerations in football betting and backing teams such as Portsmouth in this sort of match-up is the type of bet that should earn a long-term profit. The next-best away chances in the Premier League are held by Liverpool, Blackburn and Manchester City. The best value is Blackburn at Bolton in a derby which has not produced a home league win for almost eight years. Bolton have won four in a row at home in the league but, while that run was started by a 1-0 win over Manchester United, the case is far from proven that they are back to the standard of form they achieved under Allardyce. Aside from the win over United, Bolton are winless in four home games this season in league and cup against current top-half teams, with three defeats. Blackburn ended 2007 with an excellent record away to teams outside the big four, losing only three out of 16 and winning half of those matches. In a derby that is likely to be closely fought as usual, Blackburn have the edge on the handicap. The most interesting home chance is Derby, with manager Paul Jewell taking on his old club Wigan. Jewell has started to bring in players during the transfer window, but even without fresh blood at Derby it is surprising to see that Wigan are favourites for this match. It goes without saying that Derby are one of the worst sides in the history of the Premier League, but Wigan are not a great deal better and they have yet to win in 11 away trips this season, with eight defeats. Obviously this is Wigan's best chance of an away win, but they are far from certain to follow up last week's cup victory at Sunderland and are worth opposing on the handicap at least. The Italian and French leagues resume this weekend and two of the better longer-priced options are in France's Ligue 1. Lens, who have won two and lost only one of four away to bottom-half teams, have a better chance than the odds suggest at Paris Saint-Germain, who are winless in 10 at home. Caen, beaten only once in their past 12 in the league, can record a home win over second-placed Nancy. Grim up north Bolton-Blackburn derbies out of 12 with under 2.5 goals since both clubs returned to the Premier League in 2001-02: 9 Only one United Manchester United's wins from their last 12 league and cup games against Newcastle, with eight by two goals or more: 10 Way down by the Riverside Goals scored by Liverpool on their last five visits to Middlesbrough, with three draws and two defeats: 0 Coming of age Years since Tottenham's last win at Chelsea, with 13 defeats and six draws in league and cup since then:18 FORM FACT: Arsenal have won 19 out of 24 in the league against non-big four teams at the Emirates stadium, including the last 12 in a row Don't go Away games without success for Fulham, who have lost 14 out of 21 derbies on the road since their last away win against a London side: 27 SHORTLIST: Derby, Huddersfield, Northampton, Caen, Portsmouth, Blackburn. BEST BET: $150 Portsmouth (handicap, Sun). Last week: one winning bet out of one. FIXTURES TODAY Arsenal v Birmingham, Aston Villa v Reading, Chelsea v Tottenham, Derby v Wigan, Everton v Man City, Man Utd v Newcastle, Boro v Liverpool, West Ham v Fulham. TOMORROW Bolton v Blackburn, Sunderland v Portsmouth.