Sho Ito had struck twice to put Kashima in front with less than 14 minutes on the clock.
However, former Italy international Pelle scored a penalty and a goal before halftime to ensure a point for the Chinese Super League side.
"It's good that we came back into the game at 2-2," said the former Southampton forward.
"We have confidence, we are a good team, we are working hard. It's not easy to win every game, but now we have to be focussed on the next game and try to win because it's important to get the three points for qualification."
Kashima lead the group with four points after debutants Johor Darul Ta'zim held Gyeongnam FC to a 1-1 draw. Diogo scored a 68th-minute penalty to cancel out Kwak Tae-hwi's opener for Gyeongnam.
Brazilian striker Edgar Silva was on target twice as Korean FA Cup winners Daegu FC defeated former champions Guangzhou Evergrande 3-1 in Group F.
Fabio Cannavaro's side struggled throughout the first half and Edgar's double gave Daegu a comfortable lead at the break. Kim Dae-won restored his side's cushion after Anderson Talisca had halved the deficit eight minutes after the restart.
Daegu lead the group with two wins from the first two games with Japan's Sanfrecce Hiroshima joining Guangzhou on three points after they picked up a 2-1 win over Melbourne Victory.
In the west, Al Zawraa thrashed Al Wasl of the United Arab Emirates 5-0 in the first Asian Champions League game played in Iraq to move into top spot in Group A, where the Iraqis are level on four points with Iran's Zobahan.
Zobahan followed up last week's 0-0 draw with Al Zawraa by defeating Saudi Arabia's Al Nassr 3-2 thanks to Amir Motahari's stoppage time winner.
Qatar's Al Rayyan downed Lokomotiv Tashkent 2-1 to secure their first win of the campaign in Group B and, with Al Wahda of the UAE hammering Saudi Arabia's Al Ittihad 4-1, all four teams are level on three points each.
(Reporting by Michael Church; Editing by Christian Radnedge)
