I think Crystal Palace scoring 1st is the best odds because Arsenal struggle to score against teams that defend and counter attack quick and our defense is not the best against counter attacking teams. If you look at most of the goals Arsenal have conceded this season a lot of them are through counter attacks because our defense are always high in the field and we do not have the pacy defenders that other top teams have and Crystal Palace are very fast in attack.
Arsenal managed to score the first goal through Martinelli, the match was very fast because both of them played pressing and continued to attack with different tensions, entering the 40th minute Crystal Palace had more difficulty keeping up with my game Arsenal who continued to press their defense and Arsenal still quite dominated possession.
Bukayo Saka again widened Arsenal's advantage so that before the first half ended Arsenal were two goals ahead. If Crystal Palace don't play better in the second half then Arsenal will again increase the number of goals, especially if you pay attention in the first half Arsenal dominated the attack.