Chipotle appears to have found a new winning strategy in its climb back toward fast-casual dominance: delivery.

The company announced May 9 that its partnership with DoorDash led to a nearly 700 percent increase in delivery orders in its first week. It didn’t hurt that delivery fees for orders of $10 or more were free through May 6, or that this time period included Cinco de Mayo.

While Chipotle has previously partnered with Postmates on delivery in about 660 restaurants, this initiative with DoorDash is its biggest commitment to delivery yet.

“The DoorDash partnership makes delivery available from more than 1,500 Chipotle restaurants across the country—our largest delivery partnership to date—so enjoying Chipotle’s food is now even easier and more convenient,” said Curt Garner, Chipotle’s chief digital and information officer, in a release.

According to DoorDash, the average delivery time for Chipotle orders was 34 minutes, and the most frequently ordered items were burrito bowls, burritos, and chips and guacamole.

In February, Chipotle announced that it would spend $45 million to retrofit new make-lines at about 30 percent of its restaurants in an effort to increase the amount of digital orders that can be processed, including those for delivery. These digitally enhanced make-lines will be in about 1,000 restaurants by the end of the year.

CEO Brian Niccol, who joined Chipotle from Taco Bell in March, said on the company’s first-quarter earnings call in April that those units with second make-lines boast better order accuracy and have driven a nearly 20 percent improvement in customer feedback.

The addition of the second make-line will help streamline Chipotle’s booming digital-ordering platform. Mobile sales grew 41 percent, year over year, in the first quarter, and digital sales climbed 20 percent to account for 8.8 percent of total sales. Overall, Chipotle’s comparable same-store sales climbed 2.2 percent in the first quarter.