Substitute Fredrik Ljungberg scored two second-half goals as Arsenal beat Porto to win the Amsterdam Tournament.
Hleb joined Arsenal from Stuttgart over the summer
Arsenal struggled in the first half, with Porto taking the lead when Lisandro converted Jorginho's cross.
But within 15 minutes of coming on Ljungberg had put Arsenal ahead, first scoring with a precise finish and then beating Vitor Baia from close range.
Boca Juniors beat Ajax 1-0 with a goal from Jose Calvo in the other game, but Arsenal's two wins saw them finish top.
Arsenal took nine points courtesy of a bonus points system for goals scored, with Porto on six after a win and a draw.
Boca finished with four points, and Ajax, who had won the tournament for the past four years, took the wooden spoon with no points.
Arsenal laboured in the opening period against Porto, but Ljungberg's introduction after the break sparked them into life.
Philippe Senderos and Pascal Cygan looked uncomfortable with Benni McCarthy's movement and aggression in the first half.
Senderos was eventually replaced by Kolo Toure, who came on midway through the second half.
A McCarthy free-kick also almost embarrassed Jens Lehmann, when the Arsenal goalkeeper spilled the South African's shot.
Later in the game, Lehmann did better to athletically tip over the bar a dipping cross from Jorginho.
It was Jorginho who provided the cross for Lisandro's goal, the Brazilian winger's inswinging delivery cutting out both Cygan and Senderos.
Having got in front of Senderos, Lisandro side-footed the ball past Lehmann.
Arsenal's attempts on goal were sporadic, prompting manager Arsenal manager Arsene Wenger to introduce Ljungberg and Dennis Bergkamp.
The changes had an immediate impact and within five minutes of the re-start Arsenal were level.
Porto failed to clear an Ashley Cole cross, the ball reached Ljungberg and the Swede stroked the ball past Baia's dive.
Just before the hour Ljungberg, who signed a new three-year contract last week, claimed his second goal when he converted Mathieu Flamini's cross.