It is derby day in the Irish League Premier Division championship and two of the collisions will impact on the top table situation.

Portadown and Glenavon, second and third on goal difference, meet at Mourneview Park and Belfast's big two, Linfield and Glentoran, battle it out at Windsor Park.

Also in Belfast is the clash at Seaview between leaders Cliftonville and Crusaders, attracting less attention but no less important.

Critics are predicting that another failure by Glentoran to beat their old rivals could signal the end of the road for their manager, Tommy Cassidy. Cassidy may be the great survivor but the fans are unlikely to tolerate another defeat at the hands of the old enemy . And that might also go for the board f of directors.

Glenavon believe they will extract revenge for an earlier beating by their mid-Ulster neighbours and it is very much a toss-up between Cliftonville and Crusaders.