The winger starred as Wales secured a controversial 2-1 victory over the Scots in Cardiff in October and looks set to be on top form for next month's World Cup qualifier at Hampden.
Bale stole the show with a stunning winner for Spurs in Monday's 3-2 win at West Ham, meaning he has now netted eight of Spurs' last 10 goals.
That strike yield will guarantee him becoming a massive summer transfer target for many of the top-notch clubs in European football.
Scotland assistant coach McCall said: "There is some top quality in the Premier League.
"Luis Suarez is sensational and Robin van Persie is having a great season, but, for impact on a game and match-winning goals, it is certainly Bale at this moment in time. He's terrific. If we're being honest, he was the one who ripped us apart. It was a fantastic goal at the end.
"I was watching the game with my boy and he said, 'how do you stop him?'
"You've got to try to force him down one side of the park but I've still seen him smash them in from 25 yards with his right. He's just playing with so much confidence at this moment."
Hammers midfielder Joe Cole thought he had won the game last night when he put his team 2-1 up in the second half, but Bale's second strike left the Londoner in awe of the flying Welshman.
"Our goalkeeper was fantastic but you can't help the goal from Bale – it's world-class," Cole said. "He could be up there with the best players in the Premier League's history. He is great to watch, but he's a nightmare to play against, unfortunately."
