After the 8-2 humiliation against reigning Premier League Champions Manchester United at Old Trafford on Sunday, the defender's acquisition comes as a huge relief and positive sign for the Gunners.
Wenger has desired a defensive signing all summer after lingering frailties haunted the North London giants in the second half of last season. The likes of Bolton's Gary Cahill and Everton's Phil Jagielka were heavily linked with a move to the Emirates, but both were valued at close to £17 million.
Mertesacker, who is one of the highest-rated centre halves in Europe, was a presence greatly put forward by Arsenal fans and critics and The Guardian has announced the 26-year-old is set to be secured for a terrific fee of £10 million.
A hugely imposing figure, the German international is a giant at 1.98cm (6'6'') and will help eradicate Arsenal's notorious aerial weakness. A natural leader with speed and composure, Mertesacker is renowned for his clean and efficient defending. Boasting over 285 appearances for Werder Bremen and experience in the UEFA Champions League, the former Hannover 96 enforcer is a superb signing for the Gunners.
Many believed Wenger's lack of spending in the summer compared to rivals Manchester City, Liverpool, United and Chelsea was leading to their demotion down the table of English football, but Mertesacker's arrival is a lacking piece to the Gunners which will have the Wenger's men back on track to secure a top-four finish.
The German's signing ensures a highly impressive first-choice centre-half partnership with Thomas Vermaelen which will possess huge physical strength and speed alongside the ideal balance of height and power.
If Wenger is able to enforce the necessary and required attacking signings before the summer transfer window terminates, then Arsenal will be right back on track in 2011-2012.