The showpiece game of the Premier League weekend was played on a patchy surface that was covered in markings from Sunday’s NFL encounter, and reduced to dirt in some areas near the touchline.
Wembley’s ground staff had worked through the night to prepare the surface for Monday night’s game, which took place barely 24 hours after the match between Jacksonville Jaguars and Philadelphia Eagles.
The fixture was originally scheduled to take place at Spurs’ new stadium at White Hart Lane, but was relocated because of construction delays.
“To play a football game in that pitch is not easy,” said Guardiola. “That’s why there were many mistakes that usually should not happen.”
The ball appeared to bobble as Lamela fired his late shot over the bar and Guardiola added: “Lamela had a clear chance and due to the grass they did not score.
“If the grass is good, Lamela with his quality in his left foot is in a better position to score a goal.” The game was also played to a smaller-than-expected crowd as Spurs struggled to fill seats in the upper tiers of the national stadium.