(CNN) -- Two of Europe's biggest clubs staged dramatic comebacks on Tuesday as Arsenal rallied from 4-0 down to beat Reading 7-5 in the English League Cup while struggling Italian heavyweights AC Milan drew 2-2 at Palermo in Serie A.
The results will have different impacts for both coaches, with manager Arsene Wenger's position seemingly safe at Arsenal while Milan boss Massimiliano Allegri will continue to face pressure as his side's indifferent form goes on.
In Tuesday's only top-flight league game in Italy, Palermo led 2-0 shortly after halftime whereupon the under-fire Allegri changed his tactical plan to good effect, switching from his favored 3-5-2 to a 4-2-3-1 while also introducing Bojan Krkic as a substitute.
The former Barcelona player had an instant impact, teeing up a goal for Riccardo Montolivo before Stephan El Shaarawy leveled the game 10 minutes from time, with the 20-year-old's seventh league goal of the season taking him to the top of the scoring charts.
The point bought Allegri a little more breathing space as the seven-time European champions moved into the top half of the table, yet they still trail league leaders and old rivals Juventus by 14 points with just a quarter of the season gone.
With Allegri's position under constant scrutiny and club president -- and former Italian Prime Minister -- Silvio Berlusconi having been sentenced to four years in prison for tax evasion, the start to Milan's season has been anything but easy.
Wenger has also been criticized after mixed recent results, and his team -- featuring 11 changes from Saturday's hard-fought win over lowly Queens Park Rangers -- went 4-0 down after just 37 minutes against another team stuck in the Premier League's relegation zone.
Seconds before halftime, Theo Walcott scored the first goal of a special hat-trick, with his second coming six minutes into stoppage time to force extra-time.
The England international's his 120th-minute goal gave Arsenal a 6-5 lead, which was later extended by Morocco striker Marouane Chamakh's second of the match.
"The first set is for us, it was a tennis game today," joked Wenger afterwards. "There were so many turning points. The goal to make it 4-1 just before halftime was important, as was the miracle goal in the (90th) minute."
Wenger was forced to face disgruntled supporters at a stormy annual general meeting last week, where many fans were unhappy to hear him place qualification for the UEFA Champions League above winning a trophy.
The Gunners have failed to pick up any silverware since 2005 but they have now made it into the quarterfinals of the League Cup, on a night when fellow Premier League sides Sunderland, Wigan and Southampton all exited the competition.
Meanwhile, Reading became the first team to score five goals in a non-qualifying round of either the League Cup or FA Cup and lose a game.
Meanwhile, Spanish league leaders Barcelona began the defense of their Copa del Rey title with a 3-0 victory at third division team Deportivo Alaves.
Regular first-teamers David Villa, Andres Iniesta and Cesc Fabregas scored in the first-leg tie, while fellow La Liga side Valencia won 2-0 at Llagostera.
German Cup holders Borussia Dortmund reached the third round with a 4-1 win at second division Aalen, while fellow Bundesliga sides Schalke, Freiburg and Mainz also went through.