Receiving from Kelley O'Hara who bursted down the right wing, Morgan was just in place to nod home with ease near the post to break the deadlock.

Eight minutes apart from the opening score, Washington Spirit's midfielder Rose Lavelle added the second with a long-range kick, before Lindsey Horan smashed home a Tobin Heath's free kick from close range in the 32nd minute.

It was not long after break that Mewis' powerful shot enlarged the advantage to 4-0 at 50, before Morgan, Mewis and Lavelle each added a second goal of the match respectively on 53, 54 and 56 minutes.

Mewis' 50-minute score was the 800th goal in the quadrennial event's history and the four goals in six second-half minutes saw the US, the most successful team in women's World Cup history, race into 7-0 lead.

The Americans then made successful scoring in every five minutes starting from the 74th minute, with Megan Rapinoe, Mallory Pugh and Lloyd adding their names on the score board.

Thailand, who had only two shooting attempts against the Americans' 39, came up to their best chance in the 28th minute when Rattikan Thongsombut took a long-range shot to force Alyssa Naeher to make her first save.

"We accept the score today. We haven't done enough. They are very strong and they are excellent all-round," Thai coach Neungrutai Srathongvian said.

His counterpart of the United States, Jill Ellis responded: "Every team that is here has been fantastic to get to this point. To be respectful to opponents is to play hard against them."

"It's a tournament where goal differential is a criterion. This is about building momentum and so as a coach I don't find it my job to rein my players in.

"I respect Thailand, I spoke to some of them afterwards and they should keep their heads up. This is part of the growth of the game," she added.

With the big victory, the United States sit undisputedly on the top of Group F, beating Sweden, the 2-0 winners over Chile earlier on Tuesday evening in Rennes, to the second place.