Leyton Orient bounced back from a disappointing defeat against Cambridge by beating promotion contenders Portsmouth on Saturday.

Jobi McAnuff's stunning strike was worthy of winning any match but in truth the O's could have won by a greater margin.

Good chances fell to Jay Simpson and Armand Gnanduillet as well as Kevin Nolan, whose effort rebounded off off the Pompey crossbar.

However, it's at the other end of the pitch that Nolan is having a greater impact. The new player-manager has identified that Orient's weakness this season has mostly been at the back and he has clearly worked on making the O's more solid. It seems Nolan sees the defence as the key to improving Orient's fortunes.

Under Ian Hendon the O's kept five clean sheets in 31 games and in the last two games of his tenure in particular, Orient were desperately poor defensively.

His successor has managed three clean sheets in his four games so far and all three have resulted in victories. In those games Nolan has done a good job of organising his team and they have been much harder to break down.

The transformation is obviously a work in progress as the result against Cambridge showed. In that game Orient gifted the U's three goals, largely due to errors from individuals. The O's never really recovered after conceding ten minutes in, which highlights the importance of Nolan's approach in other games.

In his first match in charge Nolan clearly set his side out to remain solid first and foremost during the first half. After the break they took the game to Wycombe and scored the goals needed to win. Saturday's game against Portsmouth followed a very similar pattern.

Portsmouth enjoyed significant spells of possession in the opening 45 minutes but Orient remained disciplined, diligently keeping their shape in order to restrict the hosts' chances. The O's then looked to hit Pompey on the counter when the opportunity arose.

In the second half Orient were more adventurous in their attacking play, with McAnuff, Calaum Jahraldo-Martin, Nolan and Jay Simpson all posing a greater threat.

Those players offer quality going forward and they had the freedom to attack in the knowledge that the rest of the team were providing cover. Orient could've had a more comfortable lead but they defended resolutely to hold out for a 1-0 win. Not only did the match at Fratton Park show Nolan's continued commitment to strengthening his side's resolve it also demonstrated that he is willing to learn and make adjustments.

Both Newport and Cambridge made good use of their extra man in central midfield against Orient's 4-4-2 and Nolan clearly wanted to gain control of central areas against a strong Portsmouth side who can keep the ball.

The Orient boss opted to switch to a 4-1-4-1 shape to stifle the opposition and it worked well, with Jack Payne in particular doing a good job of winning the ball in front of the back four.

This set-up could serve Orient well in the coming weeks as they face four of the current top seven sides in League Two.

It was also good to see new arrivals Shaun Brisley and Nicky Hunt make solid debuts. The recruitment of those two players, along with defensive midfielder Nigel Atangana, shows the emphasis that has been placed on improving the defence.

All season the small squad has been an issue but Orient now have greater depth. Not only does this mean we are in a better position to cope with injuries it also means greater competition for places, which is something Nolan has stressed the importance of. A bigger squad could help prevent complacency and keep the team fresh during the latter stages of the season.

Overall the mood around the club has been boosted by Nolan's arrival. The Orient supporters have travelled in numbers all season, however the support from the 1,000 or so fans in the away end at Fratton Park was particularly vocal which shows the better atmosphere at the moment. Hopefully the positivity will continue to grow on and off the pitch.

It is of course too early to judge whether Kevin Nolan will be a success as Leyton Orient manager, but it is fair to say he has done a good job of identifying the team's problems and the signs of improvement in those areas are encouraging.

The O's will need to show their new-found defensive solidity when they host league leaders Northampton Town on Saturday.