Sometimes life can be tough at the top.
Just three days on from Celtic's humbling 2-0 defeat by Valencia in the Europa League, Brendan Rodgers' side must now navigate a troublesome Scottish Premiership trip to Rugby Park on Sunday (16:00 GMT kick-off).
Under Steve Clarke, Kilmarnock have only been beaten once by the champions, but what may also concern Celtic fans is the manner in which their side often struggle to match their usual, league-leading form after big games in Europe.
What do the numbers say about how Celtic fare after continental ties? And are Rodgers' men especially vulnerable on their return to domestic duty?
Throughout the 2018-19 season, Celtic have won seven of the 11 domestic games that have taken place directly after European matches.
This gives them a 64% win ratio from the selected fixtures.
When we compare that to Celtic's overall league form this season away from their post-European matches, we actually see that Rodgers' side average a win ratio of 82%.
When we break that down into points won per game, it paints a similar picture.
Over the course of the entire league season outside of the games after their European exploits, Celtic have averaged 2.58 points per game - but in the 11 matches that have come after European games that figure drops to just two.
That may not seem like a lot but it corresponds to 11 points dropped in 11 games. And that is quite something when we consider that Celtic have only dropped 18 points in the Premiership this season.
Goals, goals, goals
When we dig into Celtic's performances in those games to understand why they are dropping so many points, we can quickly establish a notable divergence in goals scored and goals conceded per match.
For example, Rodgers' side average 2.36 goals per game in the Premiership this season, which is not only the highest average in the division but also a remarkable turnover for a club that have missed both of their key strikers for spells in Leigh Griffiths and Odsonne Edouard, while also selling Moussa Dembele.
However, in those 11 games after midweek European ties, Celtic's average goals per match drops to just 1.73. Over the course of those games that equates to six fewer goals.
Celtic do also tend to concede more goals, but their average between both sets of games only varies by a marginal 0.08 goals per match - so although the Glasgow side are maintaining a relatively impressive defensive record, their goalscoring takes a notable dip.
Specialists in disruption
Although Celtic fans will joyfully recall the last showdown between both sides - which ended in an emphatic 5-1 win for their side - that result was the first in which Rodgers had got the better of the stubborn Rugby Park outfit under Clarke's guidance.
In September, just three days after an important 1-0 win over Rosenborg, Celtic were undone 2-1.
'Kilmarnock will relish this game'
Scotland assistant manager James McFadden on BBC Sportscene
It'll be interesting to see how Celtic cope with the pressure that Kilmarnock are going to bring.
They're well-organised, they've got a lot of attacking players - Eamonn Brophy will be back but whether he starts or not I'm not sure - so I think it'll be very difficult for Celtic.
A big thing has been made of the plastic pitch. It's probably one of the worst places you could go after a poor result midweek.
Scotland Women midfielder Joelle Murray
Celtic have been relentless in the past few weeks, but I think previously on the back of a European game Celtic have underperformed or been poor.
Killie will be looking to take advantage of that. Kilmarnock have beaten Rangers and shown this season that they don't have that Old Firm fear factor now.
They'll relish this game.