First half injuries to Savage and Speed meant tactical changes so there was no cap for Robert Earnshaw or Rhys Weston. Steve Jenkins and Daniel Gabbidon were not available through injury.
The level of City support for Wales was evident as Earnie warmed up in the second half, the noise level was at its highest as City's record breaking striker stretched at pitchside.
4 games, 4 wins. Excellent stuff. Well done Wales.
As for Neil Alexander he watched his Scotland team mates beat Iceland 2 - 1.
Report from BBC Wales
Wales 4-0 Azerbaijan
Hartson scored Wales' third goal with a clinical finish
The result stretches Wales' lead to seven points at the top of Group Nine with four games to play.
An own-goal after only 15 seconds was followed by strikes by Gary Speed, John Hartson and Ryan Giggs as Wales flourished.
Some Welsh fans were still finding their seats at a sun-baked Millennium Stadium when Wales grabbed a dream start.
Robbie Savage won possession in midfield and released Giggs towards the Azerbaijan goal.
The Manchester United winger fed a low cross across the face of the goal which rebounded off Azerbaijan captain Tarlan Akhmedov from an attempted clearance.
Wales manager Mark Hughes had demanded a positive start from his side, but such an early lead would have surpassed even his high expectations.
Hartson could have doubled the lead some five minutes later, but Azerbaijan goalkeeper Djakhangir Gasanzade dealt comfortable with his left-foot volley.
15 seconds: Akhmedov's own goal puts Wales ahead
40 mins: Speed heads home at the far post
44 mins: Hartson smashes a third into the net
53 mins: Giggs joins the scoring party
Savage was forced to leave the action after 17 minutes after picking up an ankle injury while barring down on the Azeri goalkeeper.
Walsall midfielder Carl Robinson replaced the Birmingham favourite.
Hughes had sprung a huge surprise with his team selection by drafting John Oster into the side for his first start since 1999.
Oster's inclusion on the right wing pushed Simon Davies back into the trouble right-back slot.
Hughes obviously felt the versatile Spurs man was a better option that the inexperience of Rhys Weston or Rob Edwards.
Southampton goalkeeper Paul Jones was given a huge vote of confidence by Hughes as he maintained the keeper's shirt despite a lack of first team action at club level.
Visibly rocked by conceding an early goal, Azerbaijan began to enjoy a period of possession as the first half reached the half way mark.
They failed to threaten the Wales goal, though, and the pace of Craig Bellamy and Giggs was invaluable to release the pressure with counter attacking thrusts.
Giggs gave the Azerbaijan defence plenty of problems
The Wales captain, who scored in the away tie in Baku last November, made no mistake with a free header at the far post from a Mark Pembridge cross.
And just a few minutes later, Hartson added a third with a clinical right foot volley which flew into the roof of the net.
A perfect opening half in terms of the score, but it certainly came at a cost as Speed followed Savage by hobbling off with an injury.
Wales a penalty appeal waved away on 50 minutes after Bellamy looked to have been brought down by the Azeri goalkeeper.
But the expectant Welsh crowd were soon celebrating another goal when Giggs slotted the ball past Gasanzade after catching the defence napping.
Game over - and the party atmosphere in the Millennium Stadium was now in full flow.
To their credit, Azerbaijan showed no signs of giving up.
And a thunderous left foot effort from Ruslan Musayev which rattled the Wales crossbar warned against any Welsh complacency.
But with the three points safely won, Hughes had the pleasure of introduction young Aston Villa defender Rob Edwards to the international stage for the first time.
Edwards had 20 minutes to make an impact and he certainly looked a composed performer at right back.
Paul Trollope, who replaced Speed at left back, and Davies came close to finding a fifth goal as the match reached a predictably lethargic end.