Burger King is getting good at trolling McDonald's (NYSE:MCD). Last month, it sold its iconic Whopper for a penny if customers ordered one using its revamped BK app. The catch was, you had to order it while you were near a McDonald's.

Now the Restaurant Brands International (NYSE:QSR) chain is giving away its new Big King XL sandwich if Chicago-area customers trade in a McDonald's MacCoin, the commemorative coins the burger giant handed out last year to celebrate the 50th anniversary of the Big Mac. Chicago is the home of McDonald's corporate offices.

Smartphone in a McDonald's french fry container and a sandwich

Image source: McDonald's.

The butt of jokes

As the fast-food industry leader, McDonald's is often the target of attacks by competitors. Wendy's (NASDAQ:WEN), whose social media account is seen as one of the best in the business, routinely launches jabs at its rival.

  • On National Compliment Day last year, Wendy's was challenged to say something nice about McDonald's. It tweeted, "They are absolutely amazing at freezing beef."
  • During last year's Super Bowl, it ran a 30-second spot about finding a "not so hidden gem" on the McDonald's website: It flash-freezes its beef to seal in fresh flavor. Wendy's noted, "The iceberg that sank the Titanic was frozen, too."
  • The year before, Wendy's Super Bowl ad tweaking McDonald's was set to the Foreigner song "Cold as Ice."
  • It has also tweeted: "Hey @McDonalds, heard the news. Happy #NationalFrozenFoodDay to you for all the frozen beef that's sticking around in your cheeseburgers."
  • It released on Spotify a five-song "We Beefin?" mixtape that riffed on McDonald's (and Burger King) on tracks like "Rest in Grease" and "Clownin."
  • And, of course, there was Wendy's most famous ad of all, the 1984 spot that asked, "Where's the beef?"

Through it all, though, McDonald's never acknowledged the barbs or responded in kind. In fact, when McDonald's is on social media, it's only to tout its own product line. Amplifying the competition to score social media points is not part of the burger chain's playbook, and that's by design.

Talking softly, carrying a big stick

PRWeek says McDonald's doesn't believe leaders lead by playing defense. It quotes Jano Cabrera, McDonald's senior vice president for U.S. communications, global media, and PR, as saying: "You don't stay a leadership brand by simply responding to competition. You do it by continuing to innovate and staying customer-focused."

Put another way, actions speak louder than words. Wendy's might be winning on social media, but McDonald's is winning where it counts: in its restaurants. Through the third quarter of 2018, McDonald's has posted comparable-store sales that for seven consecutive quarters  substantially exceed those of Wendy's and oftentimes Burger King.

Chart of quarterly comparable sales for the big 3 burger chains

Data source: Company SEC filings. 

Similarly, McDonald's systemwide sales also tend to be better than its rivals. Although Burger King far outpaced McDonald's in the third quarter, achieving 7.8% sales growth compared with McDonald's 2%, Burger King also recorded a 6.1% increase in new restaurants opened in the U.S., while McDonald's had 115 fewer restaurants open for the period (Wendy's systemwide sales were up 1.2% with seven net new restaurants open).

McDonald's has been through a lot of changes over the past few years as it sought to meet changing consumer tastes, getting itself back on track after losing a half-billion customers. So instead of trying to run its mouth as smoothly as Wendy's does, McDonald's concentrates on its customers' mouths. And there, its game is still as good, if not better, than the competition's.

Check out the latest McDonald's earnings call transcript.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.