West Brom manager Tony Pulis says Arsenal remain one of the favourites to win the Premier League title, regardless of their 2-1 defeat at The Hawthorns on Saturday.
Olivier Giroud gave Arsenal the lead in the 28th minute, but the hosts quickly levelled the scoring via James Morrison.
An own goal from Mikel Arteta then saw West Brom go 2-1 up before the break and a missed penalty from Santi Cazorla late in the second half saw Arsenal leave empty handed.
"It's such an important win, Arsenal are an exceptional side," Pulis told BBC Sport.
"I was a bit disappointed after the first half because they scored from a set piece and did not do much else.
"The second half, when you are 2-1 up, you know they are going to come at you. And they have such wonderful players, fantastic players. I think they have an outstanding chance of winning the title this season.
"At times we were fortunate in lots of respects, but the hard work and determination of the lads paid off.
"We got beat here the last couple of games without deserving to lose. There are such small margins between winning and losing and it's dropped our side today."