Diego Castro is the A-League's greatest ever player - Liam Reddy

Perth Glory goalkeeper Liam Reddy is adamant Diego Castro is the A-League's greatest ever player, saying the Spaniard's prolonged brilliance means he eclipses Alessandro Del Piero.

Castro has been in the hottest of form in recent weeks, helping the Glory build a seven-point lead at the top of the ladder.

Italian star Del Piero scored 24 goals in 48 games for Sydney FC, while Thomas Broich, Milos Ninkovic, Besart Berisha, and Bruno Fornaroli are other foreigners who have lit up the league.

But Reddy reckons Castro is the best, saying the 36-year-old's bag of tricks and classy style beats the rest.

"Look, Del Piero was good. But I think what Diego has done for four years speaks volumes," Reddy said.

"Del Piero was an unbelievable player, but I don't think we saw the best of him when he was here.

"I think the work Diego does off the ball as well as on the ball is exceptional.

"For me he's the best player to play in the league.

"We can give him the ball in tight spaces and he finds a way of getting out."

Castro, who played for Sporting Gijon and Getafe in La Liga, will be back in action this Saturday night when Glory host Brisbane at HBF Park.

The Glory's run of four straight clean sheets was broken in last week's 2-1 win over Melbourne Victory.

Despite conceding that late goal, Reddy has been thrilled by the team's excellent defensive displays.

Glory leaked an average of 1.9 goals per game over the past two seasons.

But that figure has dropped to 0.94 this season in a remarkable turnaround under new coach Tony Popovic.

Reddy has played with seven different A-League teams, and he says the current Perth squad is one of the best.

"It's a really tight group of players and staff," Reddy said. "We always work hard for each other and roll our sleeves up and do the dirty work."