The all-inclusive format of the FA Cup means that footballs oldest surviving tournament has seen countle s giant-killings in its history, as lower-ranked Davids slay the Goliaths above them. Non-league Hereford Uniteds victory over Newcastle in 1972, prompted by the now famous long-range effort from Ronnie Jonathan Garvin Jersey Radford, is woven into the competitions folklore, along with John Motsons fevered reaction. More recently, Wrexham, who in 1991 had finished bottom of the football league, beat English champions Arsenal 2-1 the next season, and Third Division Shrewsbury defeated Everton in 2003. No team is safe from the threat of a humiliating exit at the hands of a lower-ranked side, a proven premise that keeps the much-fted magic of the cup alive. After a week in which Swansea reached their first ever major final along with League Two Bradford City, this fourth round weekend has the potential to spring some more surprises.Millwall vs Aston VillaFans at the Den will be hoping their team can rub salt into the wounds when they meet a Villa side on a terrible run of form. Paul Lamberts men have slipped to just one point above the relegation zone on the back of some horrific drubbings in late December, placing their new manager under immediate pre sure. After becoming the third Premier League side to fall foul of Bradfords League Cup exploits, the last thing the manager needs is another blow to his young teams confidence. It would be tempting to rest players ahead of an important game against Newcastle, but the Villains squad is relatively thin, with Lambert admitting that We cannot rest four, five or six players. This may be for the best, as any sort of Taylor Hawkins Jersey victory would help to lift the atmosphere around the club.Millwall have had a good season so far, sitting five points off the play-offs, though they were unconvincing last time out in a 2-0 home defeat to Burnley. Inconsistency has been the Lions main problem, demonstrated recently when impre sive results against Brighton and high-flying Leicester were followed by a capitulation to struggling Barnsley. However, this is a club built on solid foundations. Kenny Jackett has been in charge for five years now, overseeing promotion from League One and gradually building a side which can challenge for entry into the top-flight. This will be a highlight of Millwalls season, and the Den will be roaring tonight, meaning that Villa must be prepared to face an onslaught. If they can see out the first portion of the game, the pace and power of players such as Agbonlahor, Benteke and Weimann should be enough to see the Premier League team through. However, if Millwall get an early goal, heads may go down, and we could well have a shock on our hands.Prediction: 1-1Macclesfield Town vs Wigan AthleticOn Saturday, Conference side Macclesfield will host Wigan, who sit 82 places above them in the football league pyramid. The home side are one of two non-league sides still in the cup, and after dramatically knocking out Cardiff last time round, they will fancy their chances of progre sing further. Steve Kings team have already broken new ground though, as never before in their 139-year history have Macclesfield made it to the fourth round of the FA Cup.Whether they can celebrate Alex Mack Jersey by becoming the first non-league team to eliminate a top-flight club since Sutton United beat Coventry City in 1989 depends largely on Wigans team selection. Their victory over Cardiff was partly down to the Bluebirds putting out a side which mainly consisted of inexperienced youngsters, as Malky Mackay decided to focus on gaining promotion. Roberto Martinez may be forced to adopt a similar policy for opposite reasons, as the Latics currently sit in 19th place in the Premier League. Wigans perennial struggle against relegation has limited their motivation in cup competitions in recent years, resulting in ignominious defeats to Swindon and Notts County. However, their succe sful negotiation of Bournemouth in the third round shows they are capable of beating lower-league opposition with their second string. The atmosphere at Mo s Rose will be celebratory at it will be a wonderful experience for all connected with Macclesfield, but I think this is where the journey ends. Dont expect the Silkmen to go down without a fight, though.Prediction: 0-1Brighton vs ArsenalAnother home tie for the lower-ranked side, and another plum home draw for Brighton, who so thoroughly disposed of Newcastle in the last round. A win here would certainly trump that result, with the ten-time winners having Dashaun White Jersey not lost to a lower-league club in the 16 years Arsne Wenger has managed them. Having needed a replay and a late strike from Jack Wilshere to knock out Swansea in the third round, the Gunners face another team playing free-flowing, attractive football. Gus Poyet has implemented his own style, and the results have been plain to see as Brighton have risen to seventh in the Championship. The Seagulls have also tightened up at the back this season, with the best defensive record of any team outside the promotion places. Going forward, Ashley Barnes and Andrea Orlandi could pose problems for an Arsenal back-line which will be mi sing captain Thomas Vermaelen, whos out with an ankle injury.Arsne Wengers recent team selection in cup competitions has given evidence that he is starting to acknowledge the need to bring a trophy back to the Emirates, whatever its nature. A similar line-up to the one which rapidly disembowelled West Ham should have too much for a Brighton side trying to bring about their Alfredo Gutierrez Jersey first season in the top flight since 1983. However, the Gunners are notoriously unreliable, and though Poyets aesthetically-pleasing style of football may suit Wengers team, it may also overwhelm their defence. As a result, this should be a high-scoring game, but I think Arsenals on-form attackers will see them through, just about.Prediction: 2-3