Zarate impressed McLeish with his performance in what was his first start since being signed from Qatar side Al Sadd for the remainder of the season, as James McFadden was left out after his wife gave birth.

But he blotted his copybook by going down too easily after bursting in between Pompey duo Pedro Mendes and Glen Johnson early in the first half with the result that he was booked.

McLeish said: "I need to speak to Mauro about that (the dive). It's in the culture of the South Americans, the Latins especially. I need to tell him it's well scrutinised over in this country.

"But I was pleased with his performance. He was exciting at times. It was difficult for him to come in under the circumstances with James McFadden having missed out the preparation due to his wife having a baby.

"With Portsmouth having such class players at the back, it wasn't going to be easy. But I thought Mauro acquitted himself well and he's only 20.

"Ideally he needs time to settle in. We probably expect miracles of him but he will cause teams problems between now and the end of the season."

McLeish is refusing to be downbeat despite Blues remaining anchored one place above the relegation zone after the 4-2 reversal at Fratton Park.

He said: "Looking at the way we played, it was maybe an opportunity lost. We could have taken something from the game but the end result is that we didn't.

"Most of our rivals around us would have been hoping and praying for that result but we still have a lot to play for.

"The players showed good character after we had gone 2-0 down early on and looked as if we might be in for a drubbing. They stayed together and didn't panic. A lot of teams would have capitulated.

"In the second half we looked a threat when we went forward and the scoreline flattered Portsmouth."