Dundee United\'s reward for knocking Rangers out of the Scottish Cup was to be given a home quarter-final gainst Celtic, the other half of the \'Old Firm\'. For Celtic, who are the Cup holders,  it is a third straight away tie after wins at Peterhead and Inverness Caledonian Thistle. However, in United they will face a side full of confidence following a 2-0 win over Rangers on Sunday. Peter Houston\'s side are currently seventh in the Scottish Premier League but have finished fourth and third in the last two seasons. Speaking after the draw, Celtic defender Adam Matthews said: \"There are still some good teams and United is going to be a tough game. If we can get through that, then I think we\'ve got a good chance.\" A couple of other all SPL ties are possible, with Aberdeen playing Motherwell if the Dons see off First Division Queen of the South in a replay and St Mirren, if they win a replay against Ross County, facing either Hearts or St Johnstone. Hibernian travel to Ayr United or Falkirk, who will play their fifth-round tie on 15 February  after Saturday\'s match was postponed because the pitch was unplayable. The three fifth-round replays will be played a day earlier on 14 February, with the quarter-finals staged on the weekend of 10-11 March. Scottish Cup quarter-final draw Hearts or St Johnstone v St Mirren or Ross County Ayr United or Falkirk v Hibernian Dundee United v Celtic Motherwell v Aberdeen or Queen of the South