By accident and design, Unai Emery is making changes that will benefit Arsenal in both the short and long term, and Saturday's somewhat fortuitous victory over Watford was a perfect example.

Arsenal were second-best for much of the game, conceding some clear-cut chances to Watford while squandering the few that came their way. Watford were bright, adventurous, and on top.

But an enforced change in goal on the stroke of half-time, and then a bold decision to replace the unhappy Aaron Ramsey with a fired-up Alex Iwobi after an hour turned the game in Arsenal's favour.

Bernd Leno made his Premier League debut when Petr Cech pulled a hamstring before half-time and the German goalkeeper, signed from Bayer Leverkusen for £22.5 million, made two important saves to keep Arsenal in the game.

And Iwobi gave Arsenal the extra verve and energy to score twice in two minutes in the final stages to rack up their fifth successive league win and move into the top five for the first time this season.