"It was really bad since the kick-off," Azpilicueta told the club's website. "They put the long ball and we gave straight away a corner. So we were not ready to compete. We knew that they are a very organised team, that they know very well what they have to do, and to be fair we didn't find spaces.
"I think we shot once in the first half and every time they played the long ball they looked dangerous. We lost that fight and we knew it was a massive game and we lost a big opportunity.
"They are a well organised team, they don't concede many goals, but we were not sharp enough, we were not quick enough to move the ball to find the attacking players in good positions. We were quite flat on the passes, going sideways, backwards."
Azpilicueta also dismissed the idea that the changing tactics employed in trying to get back into the game at Bramall Lane contributed to the poor performance.
"It was more about the desire, about the determination, that they were always ahead of us, that they were more determined than us, always they put the toe in before us. So these kind of things, the 50-50s and second balls, it doesn't matter the shape."