TOMORROW'S Mills Cup semi finals are eclipsed by a match of greater significance in the Leinster Senior League. Avoca and Railway Union meet at Loughlinstown, where the winners could prove to be the main threat to Three Rock Rovers at the top of the table.

Rovers have dropped only three points while Avoca have surrendered six and Railway seven. Pembroke Wanderers (down eight) should not be entirely discounted and could upset some of the challengers for their crown.

Avoca's 1-0 loss to Railway at Park Avenue early in the season has been the most damaging dent in their efforts to recapture the title. They probably are more fired up now, four months later. As they showed in overcoming youthful Annadale in the Irish Senior Cup, they have become tougher, too.

Railway, also a little less rugged, may not be able to hold out this time, despite the resolve of the O'Brien brothers and the agility of Barry Merriman.

This will be a testing weekend for Avoca before they head for Brussels for the European indoor championship. Their second XI take on Pembroke II in an Irish Junior Cup quarter final as an aperitif Loughlinstown.

As regards the Cable & Wireless sponsored Leinster Senior Cup, there can be virtually no doubt that Three Rock will reach the final, for YMCA have not sufficient resources to defend the trophy any further at Ballinteer.

The other semi final, though, will be closely fought as Carlow welcome Glenanne to the St Leo's grit surface. It was here that the Dubliners lost to a goal by tail Rynhart in last year's competition; but in this season's league, Keith Thompson reversed the result.

The speed of Roly O'Donoghue and Graham Shaw will stretch the Carlow cover, yet the industry of Roger Prestage, Karl Cope and Neville Kavanagh could yield a victory for the home team, even without their captain Michael Foley.

Carlow have some crucial home games in their attempt to avoid again. Meanwhile tomorrow, the second division leaders, UCD, race St Brendan's on unfamiliar territory at Phoenix Park. Possibly Owen Butler can salvage a point for the students by containing Dessie Farrell. Second placed Monkstown will be hoping to improve on last September's scoreless draw with St James's Gate.