The Nigerian found himself all alone with the ball at his feet on the edge of the penalty area in the seventh minute and he calmly fired beyond Cardiff keeper Tom Heaton, but admitted afterwards he was unsure whether he would get a goal or a yellow card.
“There was a doubt before I kicked the ball that I could get a yellow card for kicking after being offside,” he told reporters.
“But I had no time to look at the linesman and it was a quick one. I controlled and finished so I said I can’t get a yellow card.”
A poor clearance from Heaton was volleyed straight to Odemwingie by central defender Craig Dawson, and after he stroked the ball into the back of the net he explained referee Probert had confirmed City full-back Lee Naylor was the man playing him onside.
“I thought it was [offside],” he confessed.
“But then I thought there may have been someone sleeping that I didn’t see.
“When I scored I thought he just didn’t see from who the ball came, but because it came from our defender I was thinking it was a clear offside.
“After the referee told me it was the left-back [playing me on] so it’s a fair enough goal.”
It was the 30-year-old's 20th goal for the club since his arrival in August 2010 and it capped a good performance from the striker as he chased down defenders and made life difficult for them, but he felt he could have done even better.
“I missed a couple of chances that could’ve sealed the game earlier,” he said.
“It was a compensation to assist for the last goal.
“[I am] pleased with the win, it’s difficult with many players injured and tired.
“It was important after last two losses to get a win at home and prepare for the next very important Premier League game for us.”
Odemwingie has struggled with knee and ankle injuries so far this season which have limited him to making 18 appearances, but he confirmed that he was now feeling at the top of his game.
“I feel fully fit,” he added.
“[I’m] a little bit tired which is normal, we’ve played a lot of games but I feel fit.
“Since Wigan I’ve played all the games, I’m happy I didn’t miss any, [I’ve had] no muscle problems.”
The striker's goal makes him joint-top scorer at Albion with fellow forward Shane Long, but with Long injured Odemwingie confirmed he was pleased with the way his partnership with hat-trick hero Simon Cox was going.
“I’m pleased for him [Cox],” he continued.
“He has quality, he has a good shot. When he scored the second I said 'you should do this more often' because he has a good shot, so he has to get himself to positions where he can shoot.
“We played at Tottenham [together], we played today, hopefully the goals he scored will give him confidence and if he’s the one to play we need to make sure we help the team."
West Brom will now face Norwich in the fourth round, and the striker explained they had been prepared by manager Roy Hodgson to focus on doing well in the competition.
“He said that it’s been 50 years since they won the FA Cup,” he explained.
“It’s a good cup to win and let’s give our best, and he said he’s not taking this match lightly and he’s putting the best available team but he was serious about it yesterday in training and the pre-match talk was long and emphasised on being very serious and we’re hoping to get as far as possible in this tournament.”
However, the Nigerian reassured fans that the league was their main priority and he admitted forthcoming games were crucial to ensure they avoid being dragged into the relegation dogfight.
“As Bolton and Blackburn are picking points away, I think it’s going to get tough now,” he said.
“Every point will be important so there will be pressure coming for all clubs at the bottom of the table and it’s exciting.
“I only hope we can get all the points necessary to not have a very nervous end of season.”
West Brom face their FA Cup fourth round opponents Norwich next in the Premier League.
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