The PlayStation 4 was back on top last month.

After the Xbox One surprised everyone by outselling thePS4 in April, Sony has come charging back to own hardware sales in May, according to data from research firm The NPD Group. The Japanese publisher has confirmed to GamesBeat that its PS4 system outsold the competition in the United States, which is where NPD tracks sales. With the $55 billion worldwide console-gaming market up for grabs, it’s essential for Sony to keep its lead in sales.

“As we head into E3, we would like to thank gamers for making PS4 the top-selling console and the leader in software sales in the U.S. in May,” a Sony spokesperson said in a statement provided to GamesBeat. “We are truly humbled by this success and we look forward to sharing what’s next for PS4 at our E3 press conference on June 15.”

The PlayStation 4 has outsold the Xbox One every month this year except for April. That has helped Sony’s hardware build a substantial lead over Microsoft.

“PS4 continues to be the cumulative sales leader in the US and globally with more than 20 million consoles already in the market,” said Sony’s spokesperson.

Of course, sales momentum could change. The Electronic Entertainment Expo tradeshow starts next week in Los Angeles, and both Microsoft and Sony will have a chance to try to win over fans.