Two top Kroger Co. executives took the stand Monday in the Denver District Court antitrust trial seeking to block the grocer's $24.6 billion merger with Albertsons Cos., arguing the combination is key to competing with Walmart. "We are maniacally focused on Walmart and their pricing. For 20 years we have been focused on getting our prices closer to Walmart's," testified Stuart Aitkin, chief merchandise and marketing officer for the nation's largest grocery store chain. To ease anti-trust concerns, the two companies have agreed to spin off 413 Albertson/Safeway stores to C&S Wholesale Grocers for $1.9 billion. Consumer advocates and worker unions have criticized the proposed sale, viewing C&S as a weak buyer that won't survive long. State attorneys pursued that line of questioning on Monday, pushing Kroger CEO Rodney McMullen on whether the company chose what would be a weaker competitor without adequate management talent.