Arsenal travel to Spain on Thursday night as they look to reach the Europa League final and end their season with a trophy.
In their way stand Los Ches, who won 6-2 in their last La Liga game, and who will take confidence in Arsenal's defensive frailties in recent matches. Emery's side will have to be alert to keep out Valencia, whilst scoring a crucial away goal may all but kill off this tie.
Here's a look at how the Gunners could line up for Thursday's clash.
Goalkeeper & Defenders
Petr Cech (GK) - The 36-year-old is retiring at the end of the season and he will be hoping to add another Europa League title to an already impressive trophy haul. The Czech stopper is already a Premier League legend and will be missed.
Ainsley Maitland-Niles (RB) - Rested at the weekend, the 21-year-old will find himself guarding the right flank of Arsenal's defence. He has played more regularly under Emery and has put in some good displays as he looks to challenge Hector Bellerin for the right-back berth next season.
Sead Kolasinac (LB) - The Bosnian has put in some good performances for the Gunners down the left flank since he signed for the club. His attacking capabilities may come in useful as Arsenal chase an away goal to make things more comfortable for them on the night.
Lucas Torreira (CM) - The Uruguayan provides the Arsenal midfield with some South American fire and industry. His defensive work is incredibly important, but he also has an eye for a pass and the ability to score, attributes that might become important in this game.
Granit Xhaka (CM) - The villain of the game against Brighton, the Swiss international will be important in this game as Arsenal look to keep Valencia out whilst also springing to the counter-attack. His passing ability will be key as he aims to launch the Gunners' forward players at the Valencia defence.
Matteo Guendouzi (CM) - The youngster has been impressive since his move to London in the summer. He has often kept the more established names out of the side and with some fine performances Emery will be pleased with his progress.
Mesut Ozil (CAM) - The German will be tasked with unlocking the Valencia defence with his pinpoint passing. Capable of the spectacular, Ozil could be the difference between victory and defeat and will want to add the Europa League trophy to his cabinet.
Alexandre Lacazette (ST) - One half of Arsenal's threatening and explosive attacking duo, Lacazette was recently voted as Arsenal's player of the season. His movement and finishing ability will terrify any defence and he will be looking to fire his team into the final.
Pierre-Emerick Aubameyang (ST) - The Gabon international has been in fine form in front of goal this season, scoring 26 goals in all competitions, five of those coming in the Europa League. Along with Lacazette, he will want to add to this tally when he faces off against Valencia on Thursday.