Gunners boss Unai Emery said his team could not impose their game plan after the break following their 1-1 draw Brighton.
Pierre-Emerick Aubameyang fired Arsenal ahead after only seven minutes, but Stephan Lichtsteiner’s failure to deal with a long ball handed Jurgen Locadia the chance to level 10 minutes before the interval.
The forward made no mistake, netting his first goal since February.
Emery believed his side could have killed the game off in the first 45 minutes and struggled to find their flow again after the break.
Speaking to BBC Sport, he said: “I’m a little disappointed. I think the first half was key in the match.
“We started winning and had another two chances, and they saved from [Pierre-Emerick] Aubameyang.
“We didn’t concede [many] chances for them but they drew level. Second half we could not impose our game plan. We did not make more clear chances to win the match.
“It’s our process, we are leaving one process with the team. We can continue in our way with this point. It would be better if we won but I think the team worked well.
“If we scored our chances in the first half we could have won. In the second half we couldn’t impose our game.”
The Frenchman’s decision to axe Mesut Ozil at half-time also raised some eyebrows, but this was apparently a tactical decision only.
“It was tactical. It’s the same every match. Sometimes I change it tactically when I need something to change,” Emery explained.