Having got the assist to put England 1-0 up in the first half, Shaw's return to worldwide football had started brilliantly.
With many fearing the worst for Luke Shaw, it was reported shortly afterward that he was doing well, and had been contacting his family from within the England dressing-room to inform them of his condition.
The 20-year-old scored England's opener from Luke Shaw's cross after 11 minutes but Gareth Southgate's side were beaten following goals from Saul and Rodrigo. "Him and John (Stones) being able to rotate positions allowed us to play through midfield better".
"We know in the back of our minds that there is a lot of hard work to do from now until the Euros to first get there and then hopefully go even further than we did at the World Cup", Kane said.
Shaw was one of few brought back into the fold, and the Man United full-back left the field on a stretcher and in a neck brace shortly after half-time, following a nasty collision with Dani Carvajal.
England and Spain also face World Cup runners-up Croatia in League A Group 4 of the UEFA's new tournament created to add spice to the global calendar.
Justice Dept. should probe NY Times op-ed writer
The Justice Department said in a statement sent to Anadolu Agency it does not confirm or deny investigations. He also said it is still unclear what the consequences would be for the official.
Rashford was also replaced in added time by Danny Welbeck, after signalling to the bench that he had picked up a knock.
Southgate said the goal should have stood but admitted his side had struggled to counter Spain's passing game. But there's a level for us to go to and that's a really good challenge for us over the next couple of years.
"We need to asses over the weekend, but I think it's likely we'll need to call some players in", Southgate said.
Spain's campaign under new manager Luis Enrique began with a win against England.
"We have got 19 matches, it's not very long, but, in my opinion, we have got the best group of players in the country here".
That clash gets underway from Wembley at 7:45pm on Tuesday evening in the final outing of the latest worldwide break.