A yearslong bet on comfy bras and underwear has paid off for Japanese fashion retailer Uniqlo, as shoppers gravitated toward functional basics during the pandemic in a trend that looks set to continue in women’s wear.

Uniqlo, part of Fast Retailing Co. and founded by Japan’s richest man Tadashi Yanai, edged out bra specialist Wacoal Holdings Corp. last year to become the top seller of women’s intimate wear in its home market after doubling its market share in recent years, according to Euromonitor.

That came alongside broader gains made by Fast Retailing during the pandemic, which surpassed Zara owner Inditex SA as the most valuable clothing retailer in the world for a few weeks in February thanks to its focus on basics like sweatpants and T-shirts, as opposed to fast fashion.

Much of the success in underwear was the result of Uniqlo’s decision to double down on producing wireless bras as early as 2011, years before a global shift toward more comfortable styles including sports bras and bralettes took hold. The decision was validated during the pandemic as even more consumers sought out comfort and value which further displaced wire bras.

The success means Uniqlo is now positioned to be a big player in women’s underwear, a rarity among apparel giants such as Zara, which have not focused as much on undergarments as it is a complex and fragmented sector.

“Underwear has become a very important product for Uniqlo’s brand image and for the company to communicate the functionality of its clothes,” said Takahiro Kazahaya, an analyst at Credit Suisse AG in Tokyo. “When a T-shirt’s quality has improved, that’s hard to show. But it’s easy to convey small upgrades in a bra.”

Retail trends during the pandemic also show that there’s continuing demand for wireless bras. In the U.S, bra sales fell 1% in the second half of 2020, compared to 19% for the overall apparel industry, according to New York-based market research firm NPD. However, sales of wireless bras were up 14%.