China this month became the fifth country where consumers can use smartphones to pay with Apple Pay, and Chinese shoppers quickly embraced the Apple Inc. payment system.

In the first two days after the Feb. 18 launch, 3 million consumers linked their bank cards to Apple Pay according to China Merchants Bank, one of 19 Chinese banks involved in the rollout. The payment method can be used to pay in stores with compatible terminals and in mobile apps that link to Apple Pay.

Every Chinese consumer with a debit card and many with credit cards are eligible to use Apple Pay because Apple is collaborating with the country’s sole debit card network, China UnionPay. Banks have issued 5 billion cards that are accepted on the China UnionPay network, including 500 million credit cards, UnionPay says.

China Merchants Bank says its customers connected 1 million bank cards with Apple Pay in the first two days of the launch, representing 35% of cards connected with Apple Pay in China. Apple and China UnionPay both declined to confirm this data from China Merchants Bank.

Apple did say it is quite happy with the launch. “I would rate our first-day performance as 1,000, if the full score is 100,” Jennifer Bailey, vice president of Apple Pay, said at a mid-February press conference in China. Apple also has rolled out Apple Pay in the United States, the United Kingdom, Canada and Australia.

Apple says the 19 Chinese banks offering Apple Pay, including such major institutions as Bank of China and the Agricultural bank of China, represent about 80% of bank cardholders in China.

In addition, 16 retail chains, restaurants and online retailers in China have begun accepting Apple Pay. They include Starbucks, McDonald’s, Kentucky Fried Chicken, Circle K and the French department store chain Carrefour. Almost all of those merchants have launched promotions for Apple Pay users. For example, Starbucks offered a 15 yuan ($2.30) discount to Apple Pay users who spend 65 yuan ($10) or more.

But consumers used Apple Pay the most on the first day of its introduction to pay on the mobile app of Meituan.com, a Groupon-like Chinese service in China, according to China UnionPay. Apple says the new payment method may double the conversion rate for e-commerce apps.

Starbucks came in second in terms of Apple Pay payments on the launch day, followed by convenience store chain FamilyMart, McDonald’s and another daily-deal site, Dianping.com.

China UnionPay reported that Apple Pay users’ spent 101 yuan ($15.5) on average on the first day of the service and about 47% of purchases were above 10 yuan ($1.5).

Web-only e-retailer Vipshop, No. 4 in the Internet Retailer 2015 China 500, is among of retailers accepting Apple Pay in its mobile app, and says it received 10,000 Apple Pay orders on the first day. The company says Apple Pay could help Vipshop offer faster services to online shoppers.

Apple Pay is hardly the first payment method in China based on mobile phones and wallets. Alibaba Group Holding Ltd.’s payment affiliate Alipay says there are about 300 million bankcards linked to its mobile wallet app, and Chinese online game and social media powerhouse Tencent Holdings Ltd. says the number of banking cards connected with its mobile apps has topped 200 million.

However, Apple Pay requires fewer steps when paying in a store. An Alipay user must open the app on her phone and then click several times to generate a bar code that the cashier scans. With Apple Pay the consumer need only place her iPhone near a terminal and verify the payment by touching a finger on a button on the phone or by inputting her password. Apple Pay users don’t need to open an app or access the Internet to make a payment, Apple says.

In stores, Apple Pay runs on China UnionPay’s Quick Pass service network, launched in 2013, which uses wireless Near Field Communication technology to establish a connection between a mobile phone and a terminal. There are 4 million NFC-compatible terminals in the Quick Pass network that can accept Apple Pay, of the 20 million payment terminals that accept UnionPay cards, according to China UnionPay.

Besides Apple’s iPhone, other smartphones that consumers can use on the Quick Pass network include NFC-enabled phones from manufacturers like Samsung Group and Huawei Technologies Co. Ltd.

Apple Pay works on the iPhone 6 or 6S, the Apple watch and some versions of the iPad. Consumers can use Apple Pay with an iPhone 5 and 5S if they pair the phone with an Apple Watch.

For more Chinese e-commerce data, please click here for the Internet Retailer 2015 China 500.