The Spaniard replaced Bruce at Wigan, whose chairman Dave Whelan famously dubbed some of the former manager's signings "dodgy".
And ex-Swansea manager Martinez – who was able to add Saturday's 1-1 draw at the Stadium of Light to the 1-0 win he secured at the DW Stadium in November – reckons he has improved the Latics compared to when Bruce left Lancashire.

Martinez said: "We expected Sunderland to be direct, but we got the goal ahead that we needed and we looked a threat going forward.

"The start of the second half was vital for us. It was a lot to ask to keep a clean sheet. We put ourselves under pressure by giving the ball away cheaply. When we keep the ball, we are a lot better.

"As a team, we need to improve in that department.

"It is close in the bottom half of the table and I don't want to talk about the other teams, but our squad is a lot better than it was in the summer."

Martinez saw Mo Diame – brought in as a replacement for Lee Cattermole when he also left Wigan to join Sunderland – smash the Latics in front after the hosts gave the ball away, Matt Kilgallon's pass putting skipper Lorik Cana in a tight spot before the Albanian's uncertainty led to the opener.

Diame slammed a rocket shot beyond Sunderland keeper Craig Gordon at his near post and Martinez confessed: "It was a great strike – I have never seen him strike the ball like that before."

The Wigan boss was also shocked that the game had nine bookings and felt referee Stuart Attwell could have been stronger.

He said: "I think the referee went along with the pressure of the crowd.

"I didn't think it was a dirty match. I felt it was a well-contested game and nine bookings is incredible.

"The crowd at Sunderland puts a lot of pressure on the referee and the players.

"We have young players – we have raw talent, but you have have other attributes and to be able to cope with the direct approach that they had and I think we showed we have a got the platform to carry on improving.

"Overall, I was pleased."