The 20-year-old signed a new Celtic contract then moved to Somerset Park on loan on the eve of the new season.
After losing a goal on his debut in the 3-1 win over Morton, Doohan has kept Albion Rovers, Ayr United and Partick Thistle (twice) at bay.
Ayr won promotion on the final day of last season and are looking forward to a Betfred Cup tie away to Dundee following Saturday’s visit to Inverness Caley Thistle.
Doohan was in the Scotland u-21 squad at the end of season Toulon Tournament and is part of a promising group of young keepers at the club that also includes Conor Hazard.
Getting the chance of regular first team football is essential to his development with Ayr providing the ideal platform after being promoted to The Championship where half of the clubs have genuine aspirations towards winning promotion.