The Dutch outfit were forced to come through qualifying stages to reach the competition proper despite their performances in 2018-19, whereas Lille's second-place finish in Ligue 1 was enough to earn them a first Champions League campaign for seven years.
Liverpool may have lifted the trophy in May and Tottenham Hotspur may have gone one better than Ajax in reaching the final, but for many the Dutch outfit were the team of last season's Champions League.
Rolling back the years to their previous glory days in this competition, Ajax claimed the scalps of Real Madrid and Juventus in swashbuckling style en route to the semi-finals, where they were dramatically bested by eventual runners-up Spurs.
The heartbreaking manner of the defeat does not appear to have caused any hangover going into the new season, though, and nor has the exits of key players such as Matthijs de Ligt and Frenkie de Jong.
Erik ten Hag's side are unbeaten in 10 matches across all competitions since the beginning of the campaign, quickly rising back to the top of the Eredivisie table after claiming their first title since 2014 last term.
Indeed, even without their memorable surge to the Champions League semi-finals it would have been a standout season for Ajax as they also won the KNVB Beker to secure their first double since 2002.
Among their matches already this season have been aggregate victories over PAOK and APOEL in Champions League qualifying, although having to go the long route certainly will not faze them having done the same in 2018-19.
Ajax were the first side in European Cup history to make it all the way from the second qualifying round to the semi-finals, losing just two of 18 European outings throughout the campaign.
A trip to the Johan Cruyff ArenA is a daunting way for Lille to make their Champions League return, then, having not featured in the competition proper since 2012-13.
It is certainly a step up from their last European foray - defeat to Gabala of Azerbaijan in the third qualifying round of the 2016-17 Europa League - and they too have had to cope with the loss of a star player in Nicolas Pepe.
Christophe Galtier's side have alternated between wins and defeats in their opening five Ligue 1 games this term to sit fifth in the table, although they do come into this match off the back of a victory over Angers on Friday night.
Both of their away games so far have ended in defeat without Lille scoring, though, and they are five games without an away win in European football stretching back to 2014.
Ajax form: WWDWWW
Lille form: WLWLW
Ajax may have lost some star power over the summer, but there are key members of last season's squad still firing on all cylinders - not least Dusan Tadic.
The former Southampton man has five goals in five league games so far this term, while in all competitions he already boasts eight goals and five assists.
Donny van de Beek is a notable absentee for the home side, though, having not featured since Ajax secured their place in the group stages against APOEL.
The 20-year-old Nigerian has made a flying start to life at the club, scoring five goals in his first five Ligue 1 games to jointly top the scoring charts at this early stage of the season.
Another one to watch is 21-year-old Jonathan Ikone, who scored just eight minutes into his debut for France during the international break.
Ajax possible starting lineup:
Onana; Veltman, Schuurs, Blind, Tagliafico; Alvarez, Promes, Martinez; Ziyech, Tadic, Neres
Lille possible starting lineup:
Maignan; Pied, Fonte, Djalo, Bradaric; Andre, Soumare; Ikone, Yazici, Bamba; Osimhen
We say: Ajax 2-0 Lille
Both sides have some exciting attacking talent on display and will know that this fixture could prove crucial with Chelsea and Valencia providing the other competition in the group. Ajax came alive during the Champions League last season and have started the new one well too, so we are backing them to come away with the win.