Fire, inspired by new signing Cuauhtemoc Blanco, dominated for large periods and took the lead when the Mexican legend was rewarded for his efforts after 30 minutes.

Celtic fought back in the second half and levelled when substitute Riordan let fly with a volley late on.

Socceroo Scott McDonald could have snatched victory for Gordon Strachan's side but shot straight at Jon Busch.

Chicago were strong in defence and almost broke through after a cagey opening when Calen Carr struck the crossbar from a Blanco pass after 23 minutes.

It was left to Blanco to take charge and he put his new side ahead when he burst into the box and coolly took the ball round Artur Boruc.

Blanco tired and was replaced after 57 minutes as one of a number of changes by both teams.

Riordan's introduction provided the spark Celtic needed and a good move initiated by the former Hibernian player ended with McDonald having a shot saved by Busch.

Jan Vennegoor of Hesselink's follow-up was also blocked but Riordan's equaliser was not long in coming.