Bolton manager Gary Megson is pleased with the number of goals his side have scored this season but admits the leaky defence is a concern.The Trotters have scored nine times in their last four games but have conceded the same number to limit them to one win - a 4-1 defeat of Middlesbrough.Chelsea breezed into a 4-0 lead last weekend, only for Bolton to make a stirring second-half comeback to eventually lose 4-3, and although Megson is pleased with the contributions of several players this campaign, he would like to find more of a balance."It was one of those things we spoke about at the start of the season that we needed to score more goals," said Megson, whose side are 12th in the standings with a seven-point cushion over the relegation zone."We're never really recognised for the amount of goals we score and we're quite pleased, without being ecstatic."Kevin Davies has exceeded what we would expect from him, Matt Taylor has, Ricardo Gardner has, Gary Cahill's come up to what we expect."There's been some who haven't chipped in and that's been a little bit disappointing but the problem we've had is that although we're scoring goals, we're still letting in way too many and we're letting in goals of a similar nature and don't seem capable of stopping it at the moment so we must do that."Bolton travel to Fratton Park tomorrow to face a resurgent Portsmouth side which is unbeaten in four.Megson is aware Pompey's fans will see this clash as the perfect opportunity to pick up three points and edge further away from the bottom three, and he is expecting a tumultuous atmosphere."It's a fantastic ground," he said. "It's a great place to go and it's a really old fashioned football ground and the fans will give them the best chance of escaping relegation."The fans down there would have been looking at these two fixtures - us and West Brom last week - to take six points. They got one point last week and now the expectation is to get three points at home against us. It's a massive game for them."Sometimes the supporters don't realise how much of an impact they can have. Stoke's season has been brilliant so far but without that backing they've got I'm not sure they would have followed the same path."