There were many Arsenal fans very sad to see Olivier Giroud leave the club in January.The Frenchman had been at the Emirates since the summer of 2012 and scored more than 100 goals for the club.However, after Pierre-Emerick Aubameyang joined Alexandre Lacazette at the north London club, you couldn’t blame Giroud for wanting first-team football ahead of the summer’s World Cup.But for Arsenal to sell him to London rivals Chelsea - for just £18 million - looked a crazy decision.And that decision was made to look even crazier after Arsenal’s north London derby defeat against Spurs.With his side trailing 1-0, Arsene Wenger threw on Lacazette in the hope to earn a draw. Suddenly, the away side started creating chances but the substitute missed two absolute sitters to earn his side the point.Gooners might have been thinking: ‘Giroud would have scored those.’Well, a little more than 48 hours later and Arsenal fans got the chance to see their former player in action.Giroud started for Chelsea against West Brom and helped them to a 3-0 victory.In the first-half, he was everywhere.He picked up a nasty head injury, was clattered from behind by Jonny Evans but, most importantly, grabbed an all-important assist.Eden Hazard played the ball into his feet and he turned the ball beautifully back into the path of the Belgian, who finished with aplomb. That’s why Antonio Conte signed him.

And after seeing that assist - and his all-round performance - Arsenal fans were all saying the same thing. They insisted that Giroud would be a much better option as back-up to Aubameyang and that he should have stayed at the club.

ARSENAL FANS REACT

Check out the reaction:

Giroud did tire in the second-half due to his lack of football this season and was eventually replaced in the 61st-minute. But he caused the West Brom defence all sorts of problems before half-time and certainly showed Arsenal fans what they will be missing.