We faced that uphill battle just after the half-hour when Stephane Sessegnon slotted home the Baggies' third goal.
We quickly pulled a goal back after Kyle Naughton's cross was deflected home off Jonas Olsson and dominated the second half. Harry Kane reduced the deficit to 3-2 on 70 minutes before Christian's fine strike in the fourth minute of added time completed the comeback.
"We started really badly and if you are 2-0 down after seven minutes, you know it’s going to be a long game," said Christian, who took his tally into double-figures in all competitions, seven in the Premier League.
"We didn’t do what we did before and that’s lose our heads at 3-0. We got the goal for 3-1, had a penalty and we wanted to have a new game in the second half and we did that.
"The first goal was important, we were also unlucky with a penalty but we had the confidence that we could do it in the second half.
"It was way better in the second half. We wanted to win and we tried to prove that. We only got one point but at 3-0 down, you take that one point. We still wanted to win though."
Meanwhile, Christian had it all under control as he pinged home the equaliser.
"I think people got a bit nervous when I took a touch, people wanted me to shoot straight away, I was thinking about it, but I changed my mind and luckily I did the right thing!"
Saturday marked only the second time we've come from three goals down to draw in the Premier League - the last time was the 4-4 draw against Villa on our 125 celebration match, October 2007.