Chelsea vs. Napoli: 5 Things We Learned at Stamford Bridge

Chelsea and English football aren't done yet. But it's getting harder to say the same for Andre Villas-Boas' reputation.

Goals from Didier Drogba, John Terry, Frank Lampard and Branislav Ivanovic sealed Chelsea's 4-1 extra-time victory over Napoli on Wednesday at Stamford Bridge and sent the Blues into the quarterfinals of the Champions League with a 5-4 aggregate win.

Chelsea's comeback ensured an English presence in the Champions League quarterfinals for the 16th straight season. But for the Blues, it was much bigger than that.

The old guard of Drogba, Terry and Lampard—all of whom are over the age of 30—all scored goals and played well. Interim manager Roberto Di Matteo, meanwhile, won his third match in as many attempts since taking over for the sacked Villas-Boas.

For all the joy and relief Wednesday brought, Chelsea still have plenty of work left. Qualification for next season's Champions League is far from certain, and the challenges will only become stiffer as the competition progresses this spring.

With that in mind, here are five lessons we learned from Wednesday's match.

Facing a 3-1 deficit from the first leg, Chelsea needed leadership Wednesday night. They got it in overwhelming amounts—from the same old guys who had seen their stars dim significantly under Andre Villas-Boas.

Didier Drogba, 34, turned in a man-of-the-match performance—play-acting notwithstanding. He opened the scoring with a powerful header, created problems for Napoli's creaky defense all night as a target man and set up the winner with a brilliant turn-and-pass on the edge of the box.

John Terry, 31, steadied (most of the time, at least, but more on that later) an otherwise shaky defense and scored one of his own on a header from a second-half corner. When he left the pitch in extra time, Chelsea lost their best defender on the night.

And Frank Lampard, 33 and so devalued by Villas-Boas, slammed home the 75th-minute penalty that put Chelsea up 3-1 on the night and back to even terms on aggregate.

Two of the three played the full 120 minutes, and all three showed they can still bring the goods at the highest level. Others provided valuable contributions as well—notably Juan Mata—but without those three, Chelsea would have been lost Wednesday night.

And without them, Chelsea would have lost their last chance at European glory this season.

Villas-Boas came to Chelsea last summer after winning three trophies with Porto. Three matches after his departure from Chelsea, his reputation keeps falling.

In fairness, Chelsea's players seemed much more interested Wednesday night than they did three weeks ago in Napoli. But in truth, Villas-Boas got his team selection wrong that night, as well as his tactics.

It's a small wonder, then, that Chelsea's players didn't respond well.

Admittedly, three games form too small a sample size to fairly judge the post-AVB era. But Chelsea look like a better team than they were with the Portuguese manager at the helm.

John Terry will tell you (as per BBC) that the players didn't push Andre Villas-Boas out the door. Maybe they didn't, but the Blues' over-30 brigade sure did appear to be in charge Wednesday night.

Terry's sideline coaching in extra time was telling. While Roberto Di Matteo barked instructions along the touchline, the recently substituted Terry added his own.

There's nothing wrong with a senior player giving guidance, but one has to wonder where the line rests—and who's in charge.

Whoever it is, they got their tactics right. Chelsea attacked Napoli throughout the match and pressured the visitors whenever they had possession.

Most importantly, the Blues relied on direct, high crosses into the box for scoring opportunities. Napoli obliged, defending high balls and set pieces poorly throughout.

For now, Di Matteo is three for three. But it's impossible to know how long the run will last—and to what extent he'll remain in charge.

Napoli spurned several chances, especially in the first half.

Marek Hamsik carved out the visitors' first real chance in the ninth minute but could only poke his shot at Petr Cech's feet. Four minutes later Edinson Cavani raced onto a cross at the back post but placed his shot into the side netting.

Another minute later, Ezequiel Lavezzi beat the offside trap, burning Ramires along the way before seeing his shot saved at the near post.

The string of chances was no coincidence. Chelsea's defense struggled throughout, attaining consistency only in their inconsistency.

John Terry was solid, but his poor clearance led to Napoli's goal. And if Hamsik's volley had been a bit lower early in extra time, Napoli would have been the team with the all-important advantage.

In such a tight match, Chelsea were fortunate to get away with a few things. That won't always be the case as the competition progresses, and even though they won Wednesday night, the Blues' weaknesses glared clearly for all to see.

As the saying goes, you learn something new every day. Even in football, it doesn't always have to do with tactics and trends.

Here's one for me: Napoli's fans draped (scroll to the 67th minute) a Confederate battle flag over the railing at Stamford Bridge. Apparently, it's a fan tradition that references Napoli's status as a southern Italian town.

Whatever the reason, it was weird.

Follow Mike on Twitter: @MikeCummings37