Maxwell was gutted to see his side lose in the quarter-finals for the second season running.
It’s also the second time in three seasons that Central League side Wishaw have knocked them out.
Having knocked out holders Glenafton and East Region giants Linlithgow Rose, Rob Roy were fancied many to go all the way to their first final since 1977.
But their 2-0 defeat at Beltane Park has ended those hopes for another year.
Maxwell said: “We never took our chances when we were on top of them; you saw the way that they defended heroically.
“They then hit us with that sucker punch just after half time which we just huffed and puffed after.
“Most importantly I’m gutted for the supporters today; we need to bounce back quickly from this.”
This Saturday Rabs turn their attention to the West of Scotland Cup and a home tie with Irvine Victoria.