"It was fantastic to see two drivers of the calibre of Fernando and Michael (Schumacher) fighting for the victory until the last corner," he said.
"Michael's pace this afternoon was amazing and Ferrari are certainly back.
"Fernando nonetheless coped with it, and dominated and controlled the race in difficult circumstances. As we have seen before from him this season, it was the drive of a future champion."
Symonds should know, having worked with Schumacher at Benetton when the seven-times champion won his first two crowns in 1994 and 1995.
Alonso's victory at Ferrari's home circuit, and one where Renault have not been particularly strong of late, was his third win in a row this season and the team's fourth in four races.
It was also the first time in the modern era of Formula One that a single engine has won two races.
Alonso leads the championship with 36 points to Italian Jarno Trulli's 18 for Toyota. Schumacher, second on Sunday after starting 13th, has 10.
"I think this was my best win in Formula One so far," said Alonso, who inherited the lead from Finland's Kimi Raikkonen when his McLaren suffered a driveshaft failure.
"I was always hoping for the win after Kimi retired and I had only one picture for the race, that I was winning the race," he added. "I was ready to fight for the last laps, I really wanted the victory here."
The Spanish Grand Prix at Barcelona's Circuit de Catalunya is the next race on May 8 and, with Alonsomania catching on in Spain, tickets have already sold out.
"I know the atmosphere will be amazing," he said. "It will be completely full from Friday to Sunday and as I said before, we are at a good moment for me and the team.
"Hopefully we can finish the race and I am sure that with the performance we have, we can get a podium again. So I really hope it will be a big party for everyone."
