Robbie Fergusson retains the stand-off berth and kicking duties following his match-winning conversion last week while Josh Dunning begins in the second row.
"Last week's victory away to Plymouth Albion was well-earned," said an Ayr spokesman. "Coming back from 17-5 down at half-time to win 17-18 showed great determination and character and there has been a real buzz in training this week.
"Cross Keys will prove another tough challenge but the players will want to put on a good performance in front of the home support. Our opposition played in their first B&I Cup tie last Saturday and won comfortably agaisnt Moseley by 47-3 so we anticipate a difficult game.
Ayr 15 - Grant Anderson 14 - Michael Doneghan 13 - Richard Dalgleish 12 - Mark Stewart (captain) 11 - Cameron Taylor 10 - Robbie Fergusson 9 - Murray McConnell; 1 - Gordon Reid 2 - Hayden Wisnewski 3 - Moray Low 4 - Josh Dunning 5 - Robert McAlpine 6 - Andrew Dunlop 7 - Calum Forrester 8 - John Willis
Replacements: 16 - Stuart Fenwick 17 - Andrew Kelly 18 - Alan Brown 19 - Richard Hawkins 20 - Johnnie Beattie/ Colin White 21 - AJ McFarlane 22 - Sylvain Diez
Cross Keys: 15-Gareth David 14-Kristian Baller 13-Leon Andrews 12-Phil Williams 11-Nathan Trowbridge 10-Steffan Jones 9-Rhys Dyer 1-Richard Cornock 2-Gerwyn Price 3-Craig Gould 4-Dan Hodge 5-Tom Lampard 6-Rhys Peebles 7-Rob Nash (capt) 8-Jevon Groves
Replacements: 16-Lewis Rawlins 17-Jamie Sollis 18-Marc Jones 19-Marc Popham 20-Luke Williams 21-Nathan Williams 22-Owen Jones.