Chicago Fire's Costa Rican international Francisco Calvo scored an injury-time equaliser to deny Eastern Conference leaders D.C. United a come-from-behind victory in a 3-3 draw on Wednesday.

Calvo struck in the second minute of time added on, heading home a looping pass from Bastian Schweinsteiger to salvage a point for Chicago at Audi Field.

It was a disappointing outcome for Wayne Rooney's D.C. United, who had fought back to lead after going 2-0 down to early goals from Chicago's C.J. Sapong and Djordje Mihailovic.

Ulises Segura pulled a goal back for D.C. United just before half-time, sweeping home a low finish after a fine pass from Rooney to make it 2-1.

The Costa Rican striker then made it 2-2 in the 61st minute, rifling home a low-angled finish after a through ball from Leonardo Jara.

Luciano Acosta looked to have given D.C. United all three points in the 81st minute, steering home Jara's cross from the right after losing his marker in the six-yard box.

United appeared to be heading for a win, and a three-point lead at the top of the Eastern Conference, but Calvo's late leveller means they remain just one point clear of Philadelphia Union.

Philadelphia missed the chance to go top after being held to a 1-1 draw by the Colorado Rapids.

Elsewhere Tuesday, Zlatan Ibrahimovic delivered a goal and an assist in his first game back from suspension as the Los Angeles Galaxy notched a 2-0 away win over Sporting Kansas City.

The Swedish icon created Favio Alvarez's opener at Children's Mercy Park before burying his 10th of the season in the 86th minute to make the game safe.

Galaxy are second in the Western Conference, six points adrift of city rivals Los Angeles Football Club after 15 games.