Allamerican Bertie, ridden by Pat Day, made her turf debut a winning one, setting the pace and turning back a slight challenge at the top of the stretch for a convincing eight-length victory over Histoire Sainte in Thursday's featured $59,500 allowance race for fillies and mares at Churchill Downs.The 3-year-old daughter of Quiet American, who captured the Delaware Oaks in July, covered the 1 1/16 miles on the turf rated as good in 1:43.24 and paid $3.60, $2.60 and $2.10. Allamerican Bertie was using the turf event as a prep for $250,000 Falls City (gr. II) on dirt to be held on Thanksgiving Day, Nov. 28.Histoire Sainte, with Donnie Meche aboard, closed late along the inside to take the place spot and paid $3.20 and $2.10. Solvig, who made a bid for the lead around the far turn, settled for third and paid $2.10.Owned by Richard, Elaine and Bert Klein and trained by Steve Flint, Allamerican Bertie pocketed $37,235 to increase her lifetime earnings to $451,835. Unraced as a 2-year-old, the win was her fifth in 10 career starts, including a second in the Alabama (gr. I) at Saratoga."The worst thing that could have happened did happen," said Flint. "She won so convincingly that everyone is going to wonder why I've been racing her on the dirt. Pat was able to relax her and that was a benefit because they went the last quarter in :23 and change. I really wanted to give her a quality race going into the Falls City and this was a good one."Maybe next year we'll give her some more turf opportunities. But right now, I really want to win the Falls City for the Kleins."