"I never wrote him off, I always knew he was going to be important for us," said McClaren after Owen took his tally to 40 goals for his country in his 85th international match.
Only Bobby Charlton (49), Gary Lineker (48) and Jimmy Greaves (44) have scored 40 or more goals for England and Owen looks capable of overtaking all of them before too long.
The Newcastle United striker scored twice in the first half but McClaren praised his all-round contribution in the 3-0 victory that lifted England up to second place in Group E. Croatia lead with 23 points, England have 20 and Russia 18.
"He looks fitter and sharper, and its not just his goals, but his all-round play," said McClaren, delighted to have Owen back in the side after more than 20 months in which he has battled two serious injuries.
Owen has scored three in two games following his strike against Israel on Saturday as England collected six points out of six to revitalise their Euro 2008 qualifying campaign.
HAPPY MAC
McClaren told reporters: "I am greatly satisified. We wanted six points out of the two games and we got them and I'm satisfied by the performance of individuals and the team. But we are keeping our feet on the ground. There's three games to go, and we have won nothing yet and we're not qualified yet either."
England should beat Estonia in their next qualifier at Wembley on Oct.13, then face a tough return match against Russia in Moscow four days later.
Russia coach Guus Hiddink said England gave his team a lesson in finishing, and said that despite the loss he was still optimistic his team could qualify for the finals.
"England took the chances they created tonight and we didn't have the final pass, the final touch, the killer ball to frighten them.
"But the qualification is not over yet. England must come to Moscow and also play Croatia and this is going to go right down to the end. It is a very tough qualifying group."
Owen said: "We know there's quality in the side but all too often we haven't shown the quality. But in these last two games we've blown teams away in the first half hour."
Owen opened the scoring after seven minutes, made it 2-0 with a superb volley after 31 minutes and then provided the pass for Rio Ferdinand who made it 3-0 six minutes from time.
