Three points from Arsenal's 3-2 win over Ludogorets in the Champions League:
1. Arsenal respond to shocking start
Arsenal just can't help digging themselves into a hole.
Down 2-0 to Ludogorets after just 15 minutes, Arsene Wenger's team had to stage a spirited fightback that was finished off by Mesut Ozil in spectacular fashion with an 88th-minute winner.
It was a victory that was much tougher than it should have been and came after the Gunners showed some of the old bad habits many thought they had finally put behind them this season. But in the end, they are through to the last 16 of the Champions League with two games to spare and retained first place in Group A.
For much of the night, though, it looked like all of their good work in the previous three group games would be undone. They spent the first 15 minutes seemingly determined to rediscover their old self-destructive ways as poor defending allowed Ludogorets to take a shocking 2-0 lead. Jonathan Cafu slid in to turn home a free kick before Claudiu Keseru was left unmarked in front of goal to double the lead just three minutes later.
A day after Halloween, Arsenal were putting on a horror show against a team they beat 6-0 at home in the previous round.
But the response came quickly. Granit Xhaka turned home a goal in the 20th minute and Olivier Giroud marked his first start of the season by heading home an equaliser shortly before the break.
Arsenal were nearly exposed again in the second half and needed David Ospina to make a couple of crucial saves just to avoid a defeat. In the end, it was a moment of pure class from Ozil that decided matters.
Put through on goal, Ozil used an exquisite touch to lob the ball over goalkeeper Milan Borjan before holding off two defenders to calmly slot the ball into the net. It was a goal worthy of deciding any match and made sure that Arsenal's shaky start may quickly be forgotten. With a crucial North London derby coming up this weekend, they have little time to dwell on it.
2. Giroud shows both strengths and weaknesses
It seems Giroud and Alexis Sanchez can still coexist in this Arsenal team, although for now the Chile international should retain his role as Wenger's first-choice central striker.
Giroud's first start of the season saw Sanchez move back to the left wing with Aaron Ramsey on the right. It was a formation that was often seen last season, but that now only served to highlight just how much the team has evolved since then.
With Sanchez up front, the Arsenal attack revolves around pace and movement as he helps create space for Ozil, Theo Walcott and Alex Iwobi on the flanks. With Giroud and Ramsey among the front four, that pace largely disappears and the attacking play often looked stagnant in Sofia.
Giroud still showed the qualities he offers in the area by heading home a cross from Ramsey, and it's clear he will still have a large role to play for this team this season. He now has three goals in two games after his brace against Sunderland on Saturday, but this game gave Wenger little reason to stray from a recipe that has been so successful this season.
3. Ludogorets expose familiar shortcomings for Arsenal
Arsenal can't say they hadn't been warned. There was a sense after the 6-0 win at the Emirates that the hosts had been lucky not to concede a couple of goals in the first half, as it was the visitors that had created the better chances. The same story repeated itself in Sofia, only this time Arsenal's luck ran out.
The shortcomings that Ludogorets exposed in Wenger's team during the first 15 minutes were even more familiar. Cafu's opening goal came after hesitant defending on a free kick, with Ospina reluctant to come off his line and his defenders not able to clear the ball. The second also felt a bit cheap, as Kieran Gibbs was horribly exposed down the flank and Shkodran Mustafi wasn't quick enough to close down Keseru in front of goal.
They were nearly undone on the counterattack in the second half, but Ospina bailed them out that time by saving Wanderson's shot.
It's understandable that making so many changes at the back would affect the defensive solidity that has been one of the biggest positives for Arsenal this season, but there was no excuse for being exposed twice in such quick succession, especially since they should have expected Ludogorets to come out aggressively.
These were the types of goals that Arsenal have largely stopped conceding this season, and there is a good chance they were only a temporary relapse. When Nacho Monreal and Hector Bellerin return, so perhaps will the Gunners' solidity.
Wenger has made much of the team's depth in recent weeks, and Gibbs had played well in his two previous starts. But both he and Carl Jenkinson looked like weak links on Tuesday and Wenger better hope his two regular full-backs are fit enough to play in the derby on Sunday.