Pablo Zabaleta has revealed that Manuel Pellegrini has switched Manchester City from the zonal marking system used by Roberto Mancini to a man-to-man approach, with the right-back suggesting this contributed to the two Cardiff City goals that consigned them to defeat on Sunday.

City lost 3-2 in South Wales with Zabaleta twice losing Fraizer Campbell at corners during the second half from which the striker scored each time. While Joe Hart, the goalkeeper, was also at fault for the first of these Zabaleta said: "Two goals from set pieces for us is hard. Obviously we've changed compared to last season because we were doing zonal, now it's individual marking in the box. Sometimes it's hard. Campbell was very strong in the air and that's it."

Last season Mancini drew criticism for the zonal system in which defenders are asked to patrol specified areas in and around goal rather than a particular player.

Pablo Zabaleta, right, celebrates with Edin Dzeko, centre, after Manchester City opened the scoring against Cardiff City. Photograph: Rebecca Naden/REUTERS

City's defeat came after Newcastle United were emphatically beaten 4-0 in their opening league game. What had been the difference between that display and the performance at the Cardiff City Stadium? "It was a typical game away," said Zabaleta. "Defensively they did well, they closed the space and they didn't give us the chance to create many chances. It was a difficult game for us. We didn't defend well on set pieces and it cost us the game.

"We are disappointed because we lost the game. But I think we created enough chances maybe to get some points." The defeat came after Aron Gunnarsson cancelled out Edin Dzeko's opener, with Alvaro Negredo's first goal for City proving only a late consolation. "We need to give credit to them because I think they did well," Zabaleta added.

"Sometimes [away from home] we will find lots of teams that will take chances on set pieces because that's a way they can win games. Now we need to move on to the next game, Hull City at home. We will need to come back stronger and try to get three points."