Budweiser brewer Anheuser-Busch InBev today urged SABMiller shareholders to force its board into serious takeover talks, after the rival brewer rejected its sweetened £68 billion bid.
AB InBev said in a statement it was "surprised" that the Peroni and Grolsch firm continues to say that this proposal still substantially undervalues the business.
It added that this claim "lacks credibility" because its improved offer of £42.15 a share represents a premium of around 44% to SABMiller's undisturbed closing share price.
AB InBev also pointed out that SABMiller's largest shareholder Altria Group, which owns 27% of the brewer and has three seats on its board, backs the bid that was rejected yesterday.
The Belgium-based brewer also attacks claims by SABMiller that it has not done enough work to clear regulatory hurdles in the way of the deal, particularly in China and the US.
AB InBev said: "Together with its advisers, AB InBev has done significant work on regulatory matters and has identified solutions that provide a clear path to closing."
Carlos Brito, chief executive of AB InBev, said: "Notwithstanding our good faith efforts, the board of SABMiller has refused to meaningfully engage with us.
"Our proposal creates significant value for everybody. How long will it be before shareholders see a value of over £42 in the absence of an offer from AB InBev?
"If shareholders agree that we should be in proper discussions, they should voice their views and should not allow the board of SABMiller to frustrate this process and let this opportunity slip away."
SABMiller's share price is currently around £36.42.
Yesterday SABMiller rebuffed a sweetened takeover proposal from rival AB InBev, claiming it ''very substantially undervalues'' the business.
SABMiller chairman Jan du Plessis said his firm is the ''crown jewel of the global brewing industry''.
SABMiller had already turned down two offers of £38 and £40 a share.
AB InBev has previously said it does not want to make a hostile move for SABMiller, but turned up the heat earlier by making public details of its proposal, adding it was ''disappointed'' that SABMiller had rejected its prior approaches ''without any meaningful engagement''.
A tie-up between the two would create a global beer giant worth more than £180 billion.
AB InBev is the world's biggest beer business, while SABMiller is the global number two.
Shares in SABMiller have rocketed since AB InBev's takeover hopes were revealed on September 16.
Belgium-based AB InBev has a stable of more than 200 beers, including Corona, Beck's, Leffe and Hoegaarden.
SABMiller has brands such as Miller, Foster's, Coors and Bulmers cider. It employs around 69,000 people in more than 80 countries and has global annual sales of more than 26 billion US dollars (£17 billion).
Its suitor AB InBev has a 155,000-strong global workforce and makes more than 47.1 billion US dollars (£30.5 billion) in global revenues.
SABMiller attempted to acquire Heineken a year ago, but its advances were rebuffed.