Sergio Ramos believes he has former team-mate Iker Casillas worried after winning his 150th cap for Spain against Germany on Friday.

The Real Madrid defender reached the notable landmark in the 1-1 draw in Dusseldorf, closing the gap on goalkeeper Casillas' record of 167 appearances for La Roja.

While admitting it will be tough to catch his former team-mate, Ramos has no intention of winding down his international career in the near future.

"Iker is trembling already," he said after the game against the world champions.

"However, Iker's number is difficult to overcome, it's a source of pride to get here and I'm not going to throw in the oar now."

Spain - who saw Rodrigo Moreno's opener cancelled out by a long-range strike from Thomas Muller - continue their World Cup preparations with a game against Argentina on Tuesday.

Jorge Sampaoli's men recorded a 2-0 victory over Italy on Friday despite the absence of Lionel Messi, who missed the game at Manchester City's Etihad Stadium due to a hamstring problem.

"It is another great game, and also an important one for Russia," Ramos said ahead of the fixture in Madrid.

"It serves us very well to face them ahead of the World Cup, to meet a potential rival. 

"It is good for us and for the selections that we have in front of us, it is a team to beat together with Germany."