Arsenal were poor against Porto on Wednesday evening. The Gunners lacked any sort of cutting edge in their Champions League clash this week, and they absolutely deserved their 1-0 defeat. Many of Arsenal’s top players, quite simply, didn’t turn up on the day, and perhaps the most disappointing of the bunch was Bukayo Saka. Saka is a player you can usually always rely on to step up when the chips are down, but this time, the winger was, much like many of his teammates, largely invisible in this game. Speaking on Virgin Media Sport, Brian Kerr has been discussing Arsenal’s attacking output in th…