Pierre-Emerick Aubameyang & Arsenal's lack of ruthlessness is going to prove costly

Arsenal and Benfica played out a 1-1 draw in the first leg of their Europa League round of 32 tie in Rome on Thursday night.

But the Gunners will no doubt come away feeling a sense of disappointment seeing as they certainly had plenty of chances to win it.

Post-match, Mikel Arteta made no secret of his frustration and bemoaned a lack of ruthlessness.

Pierre-Emerick Aubameyang spurned a number of opportunities, most notably one in the first half after Hector Bellerin broke forward and rolled a delightful ball across the penalty area for the Arsenal skipper. But having somehow missed, there will be fans out there who were reminded of the club's exit from the competition last season.

The Gabonese forward missed an equally golden opportunity to put the tie vs Olympiacos to bed at the Emirates Stadium last February, and were subsequently eliminated.

As far as the 31-year-old is concerned, all was forgiven when he netted doubles in both the FA Cup semi-final and final at the end of the season - putting a shine on what had, up until that point, been a pretty miserable campaign for the Gunners.

Taking into account the fact Aubameyang scored 29 goals in all competitions last season and that he's only managed 11 so far this time around - with three of those coming in last weekend's victory over Leeds - you could argue his drop off in form has been Arsenal's single biggest issue.

Aubameyang is a victim of his very own high-standards, and having managed to persuade the player to stay at the Emirates during the summer, the form of his captain would have been the least of Arteta's concerns. To see Aubameyang struggling to replicate his previous form in front of goal having tightened the Gunners up defensively must be incredibly frustrating for the Arsenal boss.

If you're looking for something to sum up a season that has been largely disappointing so far, you needn't look much further than the captain's displays. Personal issues have had an impact on Aubameyang too, missing games against Southampton and Manchester United recently.

Arsenal are giving away fewer opportunities than in years gone by, but a lack of ruthlessness has seen them struggle in the Premier League and fail to establish a lead in their Europa League knockout tie.

While the captain is not the only player to miss chances in an Arsenal shirt this season, the regularity with which he has scored since arriving in north London means there will obviously be criticism when his form dips.

But at last under Arteta, a style is starting to emerge. The build-up play has much improved but Arsenal's inability to cap it off with the goals it deserves looks as though it could lead to another largely disappointing season and should be of concern.