GUS filed a suit in Delaware Chancery Court, alleging that ABI had wrongfully interfered with GUS's merger agreement because ABI had no legal right to make an offer for database marketing firm Metromail.
On 13 March, GUS had announced an agreement to buy Metromail for $831m (pounds 500m), or $31.50 a share, plus debt.
But rival ABI has attempted to break up the deal, alleging via a lawsuit that Metromail chose the bid from GUS without conducting a fair auction.
ABI last Wednesday topped GUS's offer with a bid at $850m in cash. Metromail said it would hold talks with ABI to evaluate the offer as part of its responsibility to generate value for shareholders. A hearing on ABI's lawsuit is scheduled for March 27 in Delaware.
GUS's counterclaim seeks an injunction against ABI from interfering with its merger agreement, or if an injunction is denied, "very substantial damages," GUS said.
Retail analysts said ABI was obviously pushing to get its bid considered. But they suggested GUS would want to avoid a bidding war when the company was also making a pounds 1.6bn hostile offer for Argos, the catalogue showroom retailer.
William Cullum, analyst at Paribas Capital Markets, said: "Lawsuits are a fact of life in the US, it's just the price of doing business there." GUS shares fell 3.5p, or 0.4 per cent, to 775.5p.
Metromail said on Friday it would talk to ABI about its offer. The company has an agreement with GUS to pay the UK. retailer $15m if the bid does not go through. ABI may make a "modest" boost to its offer if Metromail can invalidate the break-up fee, Metromail said.
GUS wants Metromail because of overlaps with its own credit information business Experian-DMT in data purchasing, software licensing and development. The two are also US neighbours, being only about 10 miles apart. GUS bought Experian, which is the largest US credit information company, in 1996 for pounds 1bn.