If you’re going to launch a bold attack on a competitor, you have to expect retaliation. Last week, Coca-Cola asked, “Is Coke Zero Sugar the best Coke ever?”, in huge campaign led by three TVCs. It cannot be surprised that Pepsi would sabotage the initiative. Pepsi is offering disappointed US Coke customers on social media a refund.

All they have to do to receive their US$2.50 reimbursement is text proof of purchase and spread their disappointment in social media with the hashtag, #MyCokeBreakUp. Pepsi is also seeding a coupon for 12 packs of Pepsi Zero Sugar across social and plans to run a dozen new TV spots promoting Pepsi Zero Sugar.

It is the second time that Pepsi has gone head-to-head with Coke. In the mid-70s it challenged consumers to a taste test in Pepsi’s Taste Challenge. Challenge commercials have run sporadically throughout the world since. Pepsi is also having a subtle dig at Coke’s new flavour flop in 1985, New Coke.

There is a lot at stake. Sugar-free is proving to be a saviour in the soft drink market that has become wary of sugar-loaded products.  Coke Zero Sugar dollar sales grew 13% on the first half of the year to become the seventh best-selling soft drink in the US, with 3.5% of the category. Pepsi’s Zero Sugar version grew 22% to own 0.8% of the category.

Todd Kaplan, vice-president of marketing, Pepsi, stated, “Our hearts ache for those whose zero sugar cola of choice seems to have a bit of a commitment problem.”