It’s a fourth successive league win for Tuchel, who has taken 13 points out of 15 to lift Chelsea into the Champions League places, with Giroud and Werner scoring in the first half to seal the points.
The signs look alarming for the rest of the chasing pack in the race for the Champions League. Newcastle, meanwhile, the Magpies are seven points above the relegation zone, though they have played a game more than 18th-place Fulham.
A fine night for Chelsea, then, and one that also included the rare sight of Kepa Arrizabalaga starting a league game and keeping a clean sheet.
If Tuchel can pull off that particular act of resurgence, he will surely be forgiven any submissions made in respect of a playing style that can sometimes seem unadventurous.
Opinion at this point comes from knowing it was Newcastle. Black, white and forever grey Newcastle.
Beyond a minor reawakening in the second half, they were poor and eventually served as the latest in a most kind run of fixtures since Tuchel came in – the games with Atletico Madrid and Manchester United next week will offer firmer ground for grand judgements.
Until then, the only conclusion must be that the new regime has done a fine job of taking apart what has been put in front of them.
While those levels of rotation from cup to league are normal enough, the retention of Kepa ahead of Edouard Mendy was somewhat more surprising dismantling what has been put in front of them.
For this meeting, Tuchel made six changes to the side that trickled past Barnsley on Thursday, with Antonio Rudiger, Jorginho, Timo Werner, Mateo Kovacic, Mason Mount and Cesar Azplicueta all back in the XI.
It was Kepa first league start since he conceded three against Southampton in October, but maybe Chelsea is not yet willing to write off such an expensive purchase. ‘We need a strong Kepa in our squad,’ explained Tuchel ahead of kick-off.
‘He had a good game in the FA Cup so we decided to give him another match to build up a little rhythm, a little bit of confidence and to trust him.’
The blessing, initially, is that Chelsea was less than shattering. They held the ball, but not much of it found its way forwards to fun parts of the pitch.
In some order, Marcos Alonso had a shot from a tricky angle saved, Tammy Abraham and Werner put a pair of headers wide and Abraham disputed for a penalty against Jamaal Lascelles.
The tackle took the player and ball and in the crunch Abraham hurt his ankle, pushing him off for Giroud. One man’s misfortune, and all that.
The goal came shortly after the half-hour and was influenced in the work on Werner, who fooled Emil Krafth into giving up some space and crossed low from the right.
Karl Darlow pushed the rescue out but from there Giroud completed. Across all competitions, it was his 10th of the season.
The second was scrappy, nudged in at the far post by Werner after a Mason Mount corner, and even then it was subjected to a VAR review.
When it was given, Tuchel and Werner yelled into the sky. So did Bruce, as it happens.
Newcastle started the second half with a bit more undertaking and even had a shot on goal.
It came from a Jonjo Shelvey free-kick and Kepa made a decent save, albeit a safe one.
A moment later Joe Willock stuck wide and 25 minutes from the time the same player urged a block from Kepa, so shortly there was some pressure. Very briefly, actually.