Messi back at the double after illness to sicken Celtic

* Barcelona proved too good for Celtic, winning 2-0 at Parkhead

* Messi, back after illness, scored both goals for Barca

* Messi struck in both halves, his second from the penalty spot

* Barcelona made the knockout stages for the 13th straight year

* Celtic were knocked out of Europe this season with the defeat

* Celtic at Man City in final group match, Barca host Borussia Moenchengladbach

The dazzling Lionel Messi returned from illness to score yet another double to help Barcelona ease into the knockout stages of the Champions League for a 13th successive year with their 2-0 win at Celtic on Wednesday.

Messi, who missed the goalless draw with Malaga on Saturday with a sickness bug, was back to his tormenting best just as he had been when scoring a hat-trick in Barca's 7-0 win in the their Group C fixture at the Nou Camp two months earlier.

Celtic were not humiliated in the same manner but Barca had too much class with Messi their executioner again, latching on to Neymar's dinked through ball to fire first-time past Craig Gordon in the 24th minute and then converting a penalty in the 56th minute.

The brace took Messi's Champions League total to 92 goals, including nine in this season's group stages alone, and though he narrowly missed a hat-trick, his genius ensured Celtic exited all European competition while Barca will progress as group winners.