The club had been looking to appoint a successor to Steve Clarke, who was sacked as West Brom manager in December, after 18 months in charge following a run of four straight defeats.
Mel was appointed on Thursday night and watched West Brom's 1-0 defeat at Southampton on Saturday from the stands before taking charge of the team ahead of their game with Everton on Monday week.
And, speaking after the defeat at St Mary's, Reid said he hoped Mel's appointment could trigger a positive run of results.
"Hopefully it will give everybody another lift now," Reid told Sky Sports. "We've seen the lift we've had in recent weeks - obviously it's a disappointing result today - but hopefully we can bounce back with a new manager coming in next week and hopefully we can see an upturn in the results and the performances."
Reid admitted he did not know too much about the 50-year-old but said he was encouraged by the fact the club seem to have secured their number one preference for the job.
"I've seen the record at Betis," Reid said. "I know they had some financial difficulties at times which obviously made it a tough job for him.
"But obviously we're looking forward to working under him and we believe he likes an attacking style of football.
"We've seen other Spanish managers come into the English game and the way they play - we've seen (Mauricio) Pochettino and how his side have set up. We're looking forward to the new challenge and the new manager coming in.
"I think it's going to be positive (the future). The club have come out and said the new manager was the first choice, the number one candidate so that's pleasing to see.
"We've got a pretty strong squad as it is but at the same time we've got a new manager so he's going to have ideas on the direction of the team," Reid added.
"It's up to us players who are in possession of the shirt to impress him and to stay in the team."