The 48-year-old served as an assistant to Steve Clarke but, after the Scot was sacked last weekend, he will go it alone in caretaker charge against Hull.
Some fans voiced their upset at Clarke's departure but he exited on the back of a six-game winless run and with just three league victories all season.
The Baggies are 16th and two places above the drop zone and although sad to see his boss leave, Downing knows results need to come quickly.
"It's very sad and I had a huge amount of respect (for Clarke)," Downing, who joined West Brom in 2009, said.
"I have learned from a very good man who has been in the game a long time and been under a lot of good managers.
"It's sad if anyone loses their job and there is a tinge of responsibility as I was part of the team.
"But he is an honourable man with integrity and he understood the decision. Now he has to forge a career elsewhere and he will do that.
"We have had a decent week and the players have responded well. We need to make sure we get the right result because three points changes everything."
Managerless Spurs are their Boxing Day opponents, with West Ham following on from that.
Downing does not know whether or not he will be in place for those games, but is ready and willing if asked.
"I've not been given a specific time," he said.
"It's been reported that I will be staying over the Christmas period, but it is a game-by-game basis. I am totally focussed on Hull.
"I will take it from there and if required over Christmas I will do that, but for now it's just Hull."
Downing has managerial experience of his own - albeit a short spell with Cheltenham six years ago - and says Clarke has told him to make sure he enjoys his time in charge.
"I have to embrace it, even if it is under different and sad circumstances," he added.
"I have spoke with Steve and he told me it is an opportunity to have a go at it. I managed at Cheltenham for 15-16 months and, even though it was a smaller club, it was still managing."
Downing gave no indication as to whether or not he wanted to be considered for the job, but having minded the shop previously after Roy Hodgson's departure, knows exactly what to do.
"I sat here 18 months ago when Roy left, so I know what the position is," he said.
"I've been here for four years and the club know my support is there.
"The powers that be will decide who comes in and who comes in with them. Dean and I will try and glue things together to make it as seamless as possible."
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- Steve Clarke