A sensational breakaway try created by Bevan French and finished by Jai Field kept Wigan in touch before they broke Huddersfield hearts to win the Challenge Cup.
Despite the heroics of Wigan's Australian duo, the Giants were on course to end their 69-year wait for a cup victory when they led 14-12.
However, winger Liam Marshall struck a cruel blow to condemn them to a 16-14 defeat in front of a 51, 628 crowd at the Tottenham Hotspur Stadium.
Huddersfield dominated the first half but could only manage a four-point lead at the break. Full-back Tui Lolohea had an off day, managing to kick just one of five attempts at goal.
Wigan speed merchant French posed a big threat on the right wing, but he was largely confined to defensive duties.
Ricky Leutele forced his way over from Lolohea's pass after 16 minutes.
Lolohea's conversion attempt bounced back off an upright and those inches ultimately proved to be the difference between the two evenly-matched sides.
Huddersfield led 10-6 at the break, Smith and Giants second rower Chris McQueen both touching down.
The Giants had kept full-back Field and French on a tight rein throughout the first half, but the latter got around Innes Senior and his Australian team-mate was in support to finish off the long-range move with a glorious try.
Smith's second goal nudged Wigan in front for the first time but Huddersfield went back in front after 57 minutes when England winger Jermaine McGillvary finished clinically at the corner.
Once again Lolohea was wide with the goal kick and that meant a tense finale, with Wigan throwing caution to the wind, and the pivotal moment came four minutes from the end when Smith kicked into space for Marshall to score the winning try.
