The Uruguay international's 75th-minute header secured a 1-1 draw against a misfiring Everton side who briefly had one foot in the Champions League places when Kevin Mirallas fired them into a first-half lead.
Mel found himself having to earn his money almost immediately as, against a backdrop of off-field issues, he coaxed an improved second-half performance out of his side which could have easily also produced a winner.
Mel will have been grateful to be able to focus on the football as Nicolas Anelka had dominated the news agenda in the days and hours before kick-off.
Club sponsor Zoopla announced it would not be renewing its shirt sponsorship deal after the furore surrounding the Frenchman's 'quenelle' gesture at West Ham last month, which has been branded anti-Semitic and racist by many observers.
There were reports the company, co-owned by Jewish businessman Alex Chesterton, had requested that Anelka be left out of the side and also he should wear a shirt which did not bear their name.
Neither happened, with West Brom awaiting a decision from the Football Association, whose investigation into the 34-year-old's actions is likely to be concluded this week and possibly as early as Tuesday.
Anelka, who has promised to not to repeat the gesture and denied he was being anti-Semitic or racist by celebrating in such a way, claiming he did it in support of controversial anti-establishment comedian Dieudonne M'Bala M'Bala, could face a five-match ban if he is charged and found guilty.
He began this game energised and motivated, but despite being significantly involved he could not have the impact he would have wanted and was eventually substituted just after West Brom's equaliser.
With Everton led by Roberto Martinez it meant there were two Spanish managers on the touchline. The expectation, even on a chilly night in the West Midlands, was for an exhibition of flowing football.
What materialised in the first half was anything but as Mel's men, no doubt eager to impress their new manager, were pulled up for a number of niggling fouls while the visitors displayed none of their usual flow and rhythm.
With the spotlight on Anelka, the Frenchman at least provided glimpses of his talent but it was mainly when operating from a slightly withdrawn position.
There were several occasions when he received the ball with his back to goal yet managed to turn his marker and thread a pass through to fellow forward Matej Vydra or Zoltan Gera running from deep, but only once did he get a sight of goal and his effort was off target.
Half-chances were prevalent. Romelu Lukaku, who spent last season on loan with West Brom, hooked an early effort wide while Matej Vydra's cross - via another Anelka through-ball - was tipped away by Tim Howard with James Morrison lurking at the back post.
Bryan Oviedo, back in the Everton side for the injured Steven Pienaar, was given the task of operating in an unfamiliar wide right role but he used the position to his advantage by flashing volleys just wide of either post in quick succession.
An off-balance James McCarthy and Mirallas both failed to test Ben Foster with shots, while right-back Seamus Coleman - with five goals in his last 10 games - saw a tame shot blocked by the combination of Liam Ridgewell and Chris Brunt.
The breakthrough goal, in the 41st minute, came out of the blue and would definitely be classed as part of Martinez's plan B.
Centre-back Sylvain Distin, returning after a three-match injury absence, launched the ball in the direction of Lukaku and he nodded it down into the path of Belgian compatriot Mirallas who easily beat Foster.
With the creative Ross Barkley missing for another couple of weeks with a broken toe, Martinez will hope Mirallas, playing centrally, can maintain this form to help sustain their Champions League challenge.
The quality did not improve greatly in the second half but the hosts, sensing Everton were not entirely comfortable, ramped up the pressure and substitute Victor Anichebe - another playing against a club he left in the summer - had a near-post chance blocked by Phil Jagielka from Anelka's cross.
When Lugano attacked the same area from Morrison's cross he had more success, powering a header past Tim Howard.
Everton tried to respond, sending on new signing Aiden McGeady for his debut late on, and although Gareth Barry's shot was diverted into the net with the last kick of the game by Distin the defender was clearly offside.