REGIS Le Bris was unmoved in his technical area at Fratton Park but the understated Sunderland boss must have been thrilled by what he was watching.

And how delighted he must be at what has been a dream first month in charge of the Black Cats.

Four games, four wins and it looked like being four straight clean sheets until Luke O'Nien's 90th minute own-goal against Portsmouth on Saturday. A first goal conceded this season won't take the shine off this latest victory for the Black Cats, though.

The opener – a Zak Swanson own-goal – was fortunate but there was nothing lucky about what followed and nothing unmerited about Sunderland’s latest success. Alan Browne and Romaine Mundle – his second goal in as many games since Jack Clarke’s exit – secured the points for Sunderland, who will be desperate for the next fortnight to pass in the blink of an eye so they can get back to it and look to build on their brilliant start.

They looked like a team enjoying themselves in the second half at Fratton Park and the 2,000+ Wearsiders in the away end undoubtedly were. They chanted about their head coach and their league position. With Watford not playing until Sunday, Sunderland are currently the only team with four wins from four. And this latest success was secured without Aji Alese, Dan Neil and before their four deadline day signings get up to speed.

Only time will tell whether the failure to land a senior striker will be costly but Eliezer Mayenda was outstanding at Fratton Park, his speed, strength and movement causing problems for the home defence throughout. He deserved a goal. Chris Rigg was equally as impressive.

The team news brought the expected two changes but there was a slight surprise at how Sunderland lined up an hour later. Alan Browne, replacing the suspended Dan Neil, looked likely to be a straight swap but it was Jobe Bellingham who played the deepest of the midfield trio.

In defence, Dan Ballard replaced Aji Alese, with Sunderland having confirmed shortly before kick-off at Fratton Park that the ankle injury suffered by the former West Ham man in training this week will sideline him for up to three months. It was an update that explained why Sunderland were so keen to add Chris Mepham to their ranks on deadline day.

None of Mepham, Milan Akesic, Ahmed Abdullahi and Salis Abdul Samed arrived in time to be registered to feature at Fratton Park but Wilson Isidor was included in the squad for the first time, named on a bench which also included youngsters Ben Crompton, Harrison Jones and Timur Tuterov, with the lack of squad depth a slight concern.

Not that Le Bris will be concerned about much at the minute.

The opening half an hour brought little in terms of goalmouth action. A header that was comfortably saved by Anthony Patterson at one end, a wayward Patrick Roberts effort and half-hearted Eliezer Mayenda penalty claim at the other.

But the game’s first real incisive attacking move brought the opening goal and while Sunderland benefited from a slice of good fortune, the Black Cats will believe they made their own luck in the build-up.

Rigg played the ball into the path of the overlapping Trai Hume, whose cross was met by Eliezer Mayenda. The striker’s low first time strike was well saved by Will Norris but Jordan Williams’ attempted clearance then bounced off Zak Swanson and into his own net.

There was suddenly a bit of a swagger to Sunderland’s attacking play. Patrick Roberts caught out the Portsmouth defence with a well disguised reversed pass to Browne and while the assistant’s flag went up, the idea and execution was applauded by Le Bris in the technical area.

Sunderland were applauded off at the break, ahead without really breaking sweat. But they soon moved through the gears in an electric start to the second half and were rewarded with two quick goals to put the game out of reach of the hosts.

Six minutes after the restart, Roberts worked his magic on the right and teed up Mayenda, whose effort was goalbound but touched in on the line by Alan Browne.

And six minutes later came the third, a fine goal started by a crunching Rigg challenge and finished with a clinical Mundle strike after a driving run and well-weighted pass from the excellent Mayenda.

Portsmouth's consolation came in the last minute when Swanson's header bounced off O'Nien and went in.