MILAN (AP) — Here are five things to know ahead of Tuesday's Group H matches in the Champions League, which sees leader Barcelona travel to second-place AC Milan and Celtic host Ajax:
This is the seventh time in three years that AC Milan will face Barcelona.
The two met in the group stage and the quarterfinals in the 2011-12 season, and again in the last 16 the following year. It was in that last match-up that Milan recorded its best result, with a surprising 2-0 victory at San Siro, but the Italian side was swiftly brought back to earth as it was crushed 4-0 in the return leg.
Barcelona had won two of the previous four matches, with two draws.
BIG WEEK AHEAD FOR BARCELONA
Barcelona has a big week ahead, traveling to play AC Milan in the Champions League and then hosting Real Madrid on Saturday.
Nevertheless, coach Gerardo Martino is packing all his firepower for Tuesday's match at the San Siro.
Gerard Pique, Alexis Sanchez and Dani Alves have been called up after resting during the squad's 0-0 draw against Osasuna, the only league match so far this season that Barcelona has not won.
Now fully-fit captain Carles Puyol leads a 22-man squad to Italy along with Lionel Messi, Neymar, Andres Iniesta and Javier Masquerano. Only Ibrahim Afellay and Jordi Alba are injured and won't be on the plane.
AC Milan's task has been made all the more difficult by injury to striker Mario Balotelli.
The Italy forward missed Milan's 1-0 victory over Udinese on Saturday with a right thigh problem and is set to undergo more tests in the buildup to Tuesday's match.
Balotelli is a major doubt for the game against Barcelona but Milan will be hoping he can at least take a place on the substitutes' bench, likely alongside Kaka, who returned to action over the weekend. The Brazilian impressed after coming on for the final 13 minutes to make his first appearance with Milan at the San Siro since rejoining from Real Madrid.
Milan's only options up front are Alessandro Matri and Robinho as forwards Stephan El Shaarawy and Giampaolo Pazzini are also injured, while M'Baye Niang was not included in the list of Champions League players.
Without a point after losing against AC Milan and Barcelona, Celtic will be on the verge of elimination if it loses to Ajax.
The double-header against the Dutch champions does not come at the best time after Celtic lost playmaker Kris Commons with a hamstring injury over the weekend while captain Scott Brown is suspended. Right back Adam Matthews is also out for three months with a shoulder injury.
The matches against Ajax are seen as Celtic's best chances to challenge for qualification but manager Neil Lennon remains cautious.
"It is silly of anyone to think they will not be as dangerous as Milan or Barcelona," Lennon said. "That is exactly the reason why myself and the rest of the coaching staff went to watch them. There were things I saw which we can exploit but there were also things that demonstrated Ajax are very talented and dangerous."
Ajax has not yet won an away match in the Dutch league or Champions League this season, but captain Siem de Jong is confident the four-time European champions can end their winless streak outside Amsterdam.
"That victory will come soon, I'm not worried about it," De Jong said.
He said Ajax needs to play its trademark passing game against Celtic, as it did in phases of the 1-1 draw at FC Twente.
"With good combinations, we kept finding a free man," De Jong said. "That's what we have to do in Scotland, and stay calm if they put us under pressure."
Samuel Petrequin in London and Michael Corder in Amsterdam contributed to this report.