Arsenal manager Mikel Arteta described one of his two-goal heroes as "unbelievable" in the Gunners' 5-0 pummelling of London rivals Chelsea on Tuesday night.
The hosts moved three points clear of Liverpool and four clear of Manchester City on a record-breaking evening at the Emirates, where they recorded their biggest-ever victory against the Blues.
A tough test was anticipated against a Chelsea side who had given Man City a terrific run for their money in the FA Cup semi-finals, only to be let down by wasteful finishing to ensure that they would end the season trophyless.
However, as the Blues put in one of their worst performances of the Mauricio Pochettino era, a scintillating and merciless Arsenal arguably put in one of their best, and it was an erstwhile Blues man who played a significant part in the rout.
Kai Havertz - who departed Stamford Bridge for £65m last summer - was guilty of some poor decisions in the final third, but he atoned for those mistakes with a fine brace to continue his renaissance in red and white.
'Kai was unbelievable in all departments
The Germany international - starting in the number nine slot again - firstly latched onto Martin Odegaard's astounding through ball, easily shrugged off Marc Cucurella and finished into the roof of the net to extend Arsenal's lead to three.
Just eight minutes later, Havertz notched his second of the evening with a composed finish off the inside of the post to move onto 11 Premier League goals for the campaign, his best-ever return in the top flight.
The former Chelsea man now has seven strikes and four assists to show from his last 10 Premier League outings, and he did not hesitate to celebrate against his old team after his first strike of the evening.
Speaking in his post-game press conference, Arteta could not answer how his number nine felt scoring against the team he represented for three years, but he could not help but wax lyrical about his display.
"He was unbelievable in all departments and obviously when you have a nine score two goals the way he scored, his contribution was great and a question about scoring against Chelsea for him, but I'm sure he's very pleased," Arteta said.
Arsenal enjoy perfect North London derby preparations
Before Havertz stole the show in the second half, Arsenal exploded out of the blocks against the Blues and deservedly went ahead inside the opening four minutes, as Leandro Trossard found a gap at Djordje Petrovic's near post.
Chelsea had their goalkeeper to thank for keeping the scoreline down for the remainder of the first period, and Pochettino's men were a threat on the break in the opening 45, but the visitors were torn to shreds in a second-half whitewash.
Right-back Ben White joined Havertz in the two goals club, firstly benefitting from a ricochet after Chelsea failed to deal with a corner and coolly curling home into the bottom corner to double Arsenal's lead.
Following Havertz's double, White notched his maiden Premier League brace in unorthodox circumstances, as his cross-cum-shot deceived Petrovic and flew into the far side of the net.
The Englishman had a bewildered expression on his face as his sliced attempt capped off a near-perfect evening for Arsenal, who have laid down quite the marker ahead of Sunday's North London derby against Tottenham Hotspur.
