Fifa 10 is the first game in the supermarket rivalry!
With Tesco offering it as 1p under £29 and Asda offering it for £25 for 24 hours!
A link can be found here;http://www.videogamer.com/news/fifa_10_to_spark_retail_price_war.html
This has happened for the last couple of years so is sure to happen :)
You can also pre-order at ASDA in case of limited availabilty.