While he was often used as a substitute by Arsene Wenger, the Nigerian striker still weighed in with some important goals, as well as playing his part in two Premier League title successes and a further two FA Cup triumphs.
Yet, the development of Thierry Henry as one of the world's most clinical frontmen started to limit Kanu's appearances even further, which ultimately resulted in his move to newly-promoted West Bromwich Albion in the summer of 2004. Although he had a role in keeping the Baggies in the top flight, his miss from only a couple of yards against Middlesbrough was the most memorable moment of his first campaign at The Hawthorns.
However, during a second season which ended in relegation for West Brom, Kanu still weighed in with some important goals, including one when his former employers arrived in the Black Country nine years ago today.
Arsenal were without an away victory when they arrived at West Brom, but they broke the deadlock in the 16th minute. Jose Antonio Reyes's corner found centre-back Philippe Senderos, who volleyed past Chris Kirkland.
The visitors continued to pepper the West Brom goal with shots, but Kirkland and his defence stood firm and that stubbornness was rewarded seven minutes before the break when Kanu pounced. Senderos failed to clear Martin Albrechtsen's cross and when the ball broke for Kanu, he fired his shot beyond the reach of Jens Lehmann.
It was the first goal that the North Londoners had conceded in 338 minutes of Premier League football and although they continued to create opportunities after the restart, it did seem to sap their confidence somewhat.
The hosts would take advantage of that 14 minutes from time when substitute Darren Carter struck the winning goal. A loose ball fell kindly for the midfielder 25 yards from goal and having controlled it on his chest, he then lashed a rising effort into the top corner.
Speaking after the final whistle, match winner Carter told BBC Sport: "I just caught it as sweet as I could and it's managed to go in. It's one of those moments that I'll look back on with a lot of pride. I haven't scored a better goal than that to be honest, not even in training. It's a great moment."
Meanwhile, West Brom manager Bryan Robson added: "The lads showed great spirit to come back from the position we've been in. People have always been saying we must be down and it's never been like that."
As for defeated boss Wenger, he offered: "It was a strange game. We had plenty of chances and the goals we gave away were without any real danger. We played with a good spirit and showed great potential, but we lacked maturity and with a bit more experience we would have won this game easy."
WEST BROM: Kirkland; Albrechtsen, Davies, Clement, Robinson; Watson, Wallwork (Carter), Greening, Kamara; Horsfield (Ellington), Kanu (Moore)
ARSENAL: Lehmann; Lauren, Toure, Senderos, Clichy; Ljungberg (Eboue), Fabregas, Flamini (Owusu-Abeyie), Pires; Reyes, Bergkamp