Ride-sharing startup Lyft has new capital and a new ally in its war against Uber.

Japanese e-commerce giant Rakuten led a $530 million round of funding for Lyft in a deal that closed this week. The financing, which also included new investor Fortress Investment Group , values three-year-old Lyft at more than $2.5 billion.

The capital gives Lyft more ammunition in its uphill battle against larger foe Uber, which has raised over $5 billion in funding and is available in more than four times as many cities. The two companies have undercut one another on prices, poached drivers and sworn investors to secrecy in their efforts to expand services they believe will play a big role in the future of urban transportation.

John Zimmer, Lyft’s co-founder and president, said the new capital is primarily aimed at taking market share away from Uber in the U.S., where a growing number of people rely on the apps for their regular commutes. The company, which has yet to crack international markets like Uber has done, is available in 65 cities.

Scott Weiss, general partner at Lyft investor Andreessen Horowitz, sees the company beating Uber by emphasizing better customer service from drivers and building more loyalty with passengers. He compares Lyft’s opportunity to Southwest Airlines LUV +2.10% and Virgin America VA +1.61%, which became competitive with more established airlines by selling themselves as more customer-friendly.