Conor O'Shea was left frustrated by Italy's display against Namibia, despite his side starting their Rugby World Cup campaign with a 47-22 victory in Osaka.

Italy started a World Cup campaign with a win for the first time since 1991, with the Azzurri scoring seven tries in their encounter with the Pool B minnows.

It was not all plain sailing as Namibia struck first before O'Shea's side sparked into life.

A brilliant offload from Federico Ruzza's teed up Tito Tebaldi to burst clear and put Italy in control before half-time, and they tightened their grip after the interval.

However, with matches against South Africa and defending champions New Zealand still to come, O'Shea was not impressed with what he saw.

"We'll have to move on from that pretty quickly," he said. "It wasn't very pretty. There were too many errors in it and it was difficult conditions at times in the second half, which doesn't excuse it.

"We're disappointed with the way we played. We have a job to do in these first two games and you know that's not the true version of us, but we'll improve massively by the time we come to Thursday.

"It's a quick turnaround and you make lots of changes when you have the game in the bag that sometimes you shouldn't but you lose the continuity you might have started to build up.

"We just didn't get the pace into the game that we wanted. It was difficult out there and credit to Namibia anyway, but we'll take five points and we'll move on quickly."

Player of the match Ruzza, meanwhile, believes Italy deserved the win, having managed to overcome some turbulent weather conditions in Osaka.

"It was a tough match, the first of the World Cup, so everybody wants to put in a good performance. It was a very tough first half," Ruzza said.

"But we stayed in the game, respected the game plan and managed to get the points.

"We managed the conditions well, played well in the line outs. Now we turn the page for a tough match with Canada."