Santi Cazorla missed a late penalty, Arsenal lost Francis Coquelin and it all resulted in a 2-1 loss at the Hawthorns.
Santi Cazorla got Spain's only goal in the first half against Luxembourg despite dominating play.
Santi Cazorla, who had only one year remaining on his current contract, has signed a new deal with the club committing his future.
Santi Cazorla has seen his role continue to morph throughout the season but he has generally kept up his strong fantasy performances.
Santi Cazorla scored from the penalty spot and rebounded with a huge match after two consecutive poor matches.
There were lots of heroes with Arsenal winning 5-0 but Santi Cazorla was the biggest star with a goal and two assists.
Santi Cazorla scored a goal, got an assist and worked the center of midfield to perfection as the architect of a 2-0 Arsenal upset of Manchester City at the Etihad.
With a host of attacking players returning to health, Santi Cazorla may see his minutes diminished or his positioning on the field adjusted.
Santi Cazorla squandered a glorious opportunity late in the first half against Southampton when he shot directly into Fraser Forster's gut.
Santi Cazorla continued his prolific fantasy season in Week 19 with a goal in Arsenal's 2-1 win over West Ham.
Santi Cazorla reversed the flow of play by drawing a penalty that saw Arsenal take a 1-0 lead on the way to a 2-1 win at Upton Park.
Arsenal's attack was in sharp form, carving through the Newcastle defense with ease, and it was a pair of goals for both Santi Cazorla and Olivier Giroud that did the damage in a 4-1 thrashing of Newcastle United.
Santi Cazorla finally opened his Premier League account for Arsenal in the 3-2 loss at the Britannia on Saturday.
Jack Wilshere's injury may render this irrelevant but it is worth noting that for an important match, Santi Cazorla was left out of Arsene Wenger's starting line-up.