The showdown between Walmart and Amazon is heating up – just in time for the holidays.

Walmart, which has worked hard to shed its image as an old-school retailer, this month offered proof that its efforts are working: Online sales rose 50 percent, the company said, as more Americans flocked to Walmart.com for everyday items.

“Walmart is firmly on the advance, both in its home market and elsewhere,” said Neil Saunders, managing director of GlobalData Retail. “From our data, it is clear that Walmart is not only getting existing customers to spend more online but is also attracting new shoppers.”

The online sales growth bodes well for Walmart as it enters the critical holiday shopping season. The retailer – which last year had $486 billion in revenue, more than three times Amazon.com’s $136 billion – has spent the past year aggressively expanding its online reach. It has spent billions buying up e-commerce sites like Jet.com, ModCloth and Bonobos and has invested heavily in online grocery and same-day delivery programs.

Walmart – which tends to have sprawling stores in the outskirts of towns – is also making an effort to move into urban markets. In October, the company bought courier service Parcel as part of an effort to provide same-day deliveries in New York. Its $3.3 billion acquisition of Jet.com last year was also a move in that direction as it looks to win over more affluent, urban shoppers from rival Amazon.

It has also beefed up its website: Walmart.com now offers 70 million items, more than three times what it did a year ago, and carries high-end brands like KitchenAid and Bose. Last week, the company announced that it would also begin selling items from Lord & Taylor, the upscale department store chain, on Walmart.com.

“Our goal is to create a premium fashion destination on Walmart.com,” said Denise Incandela, head of fashion for Walmart U.S. eCommerce. “We see customers on our site searching for higher-end items, and we are expanding our business online to focus on adding specialized and premium shopping experiences.”

The earnings release came as Walmart prepared to double-down on online and in-store discounts ahead of Black Friday. The company began offering holiday discounts in early November with $1 flashlights and $245 laptops and will offer “doorbusters” deals online beginning at 12:01 a.m. Thanksgiving Day. Stores will open at 6 p.m. on Thanksgiving.

Overall, Americans are expected to spend about $680 billion this holiday season, marking a 3.6 percent to 4 percent increase from last year’s $655.8 billion, according to estimates by the National Retail Federation. But analysts predict a fierce competition among retailers and said a handful of companies, including Amazon and Walmart, are likely to see much of those gains. (A recent survey from accounting firm BDO, for example, found that more than 25 percent of Americans plan to do most of their holiday shopping on Amazon.com this year.)

“There is definitely money to be spent this season, and both Walmart and Amazon are likely to pull customers from other competitors,” Saunders said.