It was hard to envisage Arsenal’s week improving even more after they secured their first Premier League title in 22 years. But, even in the context of the club’s prolonged celebrations, Thursday brought a timely and pleasant surprise.The players reconvened at the club’s training ground, back where they had watched Manchester City fail to defeat Bournemouth, after a day off in midweek. The usual suspects ambled out on to the grass but, with part of the session open to the media, the last man to emerge from the building drew the cameras’ focus.Mikel Merino was back.The 29-year-old has become a cult hero since signing last summer with his 15 goals, many of them important, coming as a result of experimental shifts up front. But the Spaniard has not played since January due to a fracture in his right foot. And yet here was the midfielder running smoothly through the customary tunnel of slaps Arsenal players give to team-mates who are returning for their first training sessions.With the Champions League final and a World Cup spot still to play for, this moment meant something.Mikel Merino has returned to training with Arsenal (Jasper Wax/Getty Images)“Honestly, this morning I woke up and I was feeling like the first day of school,” Merino told reporters after the session. “Being around my team-mates for the first time again was unbelievable. To get all that love from them is great.”This was just a light session for the Spain international, who is due to rejoin group training fully today. As part of his individualised session, he stayed on the grass with manager Mikel Arteta and his coaching staff once all his team-mates had returned inside.They put him through his paces running a drill which involved moving the ball between them with quick passes, testing how quickly he could pass under pressure into a specific small goal from different angles and then making it into the penalty area to finish a cross. The example below was supplied by Arteta himself.