The striker scored the second goal in the 2-1 win over Manchester City on Monday.
The Frenchman has stepped up for the Gunners amidst and injury crisis this season, and is currently the top goalscorer in the side.
He added another goal to his tally on Monday evening as he scored the second in his side’s 2-1 win over Manchester City at the Emirates.
That goal was his latest in a big game for the side, following a hat-trick in the crunch clash with Olympiacos in the Champions League, and Henry has praised him for finally stepping up for the side.
“He's finally doing it against the big teams. His work-rate is second to none,” he told Monday Night Football.
The question now for Arsene Wenger is who he chooses as his first choice centre forward when everyone is fully fit.
The Frenchman now has eight goals in his last ten games for the Gunners, with fifteen in all competitions so far, and is enjoying the kind of form that makes him almost un-droppable.
With Theo Walcott back fit though Wenger must decided if he sticks with Giroud or returns to starting Walcott, who had impressed in the central role earlier in the campaign.