Tobin Heath controls a long ball forward, cuts inside into the box and touches it past Mapi Leon, who brings her down. Definite penalty.

Whistles from the fans as Tobin Heath concedes a free-kick for a shoulder barge on Leila. Well it was shoulder on back of shoulder.

Lucy Ward
Former Leeds United Ladies striker on BBC Two

That first ball from Spain was further forward than it has been so far (in the tournament).

You can see they're playing higher, with a front press. You cannot let this USA team play.

Alex Morgan is left on the turf by a Spanish tackle. She went off at half-time against Sweden with a knock but was fine to play today.

Spain have the first chance within a minute. The ball drops on the edge of the area to Patri Guijarro and her powerful shot is blocked by the face of Becky Sauerbrunn. Brave from the US defender.

Ten seconds in before the referee blows her whistle and gives Spain an uncontested drop ball. Not sure what happened there.

Under way in Reims

Tom Garry
BBC Sport in Reims

Image source, BBC Sport

This crowd are in the mood - all expectations are for a good game tonight.

If Spain are nervous ahead of their biggest ever Women's World Cup match, they aren't showing it during the anthems.

Tom Garry
BBC Sport in Reims

Image source, BBC Sport

USA fans have returned to Reims in their thousands, flocking back to the scene of their 13-0 demolition of Thailand 13 days ago.

Speaking to lots of them outside the ground, they're all very optimistic of another win tonight (although one with not quite such a large winning margin...)

National anthems time. Almost ready to go.

Alex Morgan is the joint top scorer in the tournament with five goals - albeit they were all against Thailand.

She's averaged a goal every 27 minutes in France - and set up another three goals.

Morgan is level with Sam Kerr, whose Australia have already been eliminated.

Spain have had a full three days extra to prepare for tonight's game in Reims.

They finished their group games on Monday, with USA playing Sweden on Thursday.

The winners of today's game play hosts France in Paris on Friday.

The USA topped Group F, winning all three games against Thailand, Chile and Sweden - with an all-time record of 18 goals in the group stages.

Spain finished second in Group B, beating South Africa, losing against Germany and drawing with China to finish above them on goal difference.

Image source, .

Hope Solo
Former US goalkeeper and World Cup winner

I don't think anybody can criticise this USA side. They've been absolutely been dominating. Today will be their first test.

Image source, Reuters

Sean: The USA are a great team. But this is not their World Cup. Other countries have caught up. Younger players from other countries are better. USA relies on older stars, in good condition, but an aging team with no good youth program. Spain could nip this 2-1.

Spain coach Jorge Vilda - who has a full complement of players - will stick to his passing principles against opponents who are renowned for their high energy pressing.

"We will try to be ourselves, to keep our game philosophy. Our style is recognisable, but when you face this kind of big team it is more difficult to put your game in place," he said.

"USA have a great tactical and technical level, they are very fast in transitions, they have some of the fastest and most dangerous players in the world.

"We know that they did not concede a goal in the last seven matches, and that they have scored 47, but the stats are there to be broken."

Image source, Getty Images

The USA used all 18 outfield players in the group stage.

"You have to be measured once you reach six points; sometimes you don't have that luxury but part of the plan was not just about resting legs but activating other players so they are ready for these moments," boss Jill Ellis said.

"I don't build a tournament but it seems like there have been big discrepancies at times. But when you enter a tournament as one of the last teams to play, there will be certain differences in the windows.

"The players know that and we are very used to a three-day window. For us everything was about making sure our recovery was after the Sweden game."

USA have won each of their past eight matches at the Women's World Cup by an aggregate score of 29-2. They have only conceded in one of their past nine WWC games - 5-2 v Japan in the 2015 final.

Spain are appearing in the Women's World Cup knockout stage for the first time. Only one of the past eight knockout debutants have progressed to the next round - with France beating England on penalties in the 2011 quarter-finals.

Image source, Getty Images