Microsoft is putting a squeeze on Slack in the workplace communication market with an ad spot for Microsoft Teams. Specifically, a 30-second ad debuted yesterday for the NFL playoffs. The first ever ad for the service will also air in the United Kingdom, France, and Germany in February.

Called “The Power of Teams”, the ad starts with mundane business meeting, including familiar charts, and good old speaker phones. Attendees are using printed paper. However, the ad morphs into Microsoft Teams managing the whole meeting with modern features.

It is worth noting the devices being used are Microsoft Surface, so this is a backdoor ad for the product line too.

What’s interesting is Microsoft is clearly flexing its muscles against rival Slack. With its vast resources, the company arguably has an advantage over Slack in the workplace chat market. Certainly, adoption numbers seem to show this is the case.

In recent months, Microsoft has been basking in the glory of Teams success. The company confirmed the platform has over 20 million Daily Active Users (DAUs). This number is significantly higher than Slack’s 12 million. However, Slack quickly refuted Microsoft’s numbers as not as impressive as they seem. Later, a CNBC survey has found Microsoft Teams is used twice as much as Slack.

Slack argues Microsoft Teams numbers are not that impressive at all. Microsoft says its service has 20 million active daily users and 27 million voice or video meetings were held last month. Slack says this means only a little over 1 monthly voice/video call per users.

Microsoft says Teams had 220 million filed edited, stored, or opened on its platform last month. As Slack points out, this would only mean 11 monthly actions related to files per active daily users.