The former Blancos coach is extremely wary of his old side's attacking potential, but he was quick to point out that the Bavarians also have plenty of goals in them
The Blaugrana have been lauded as one of the finest teams of all time but it has been claimed the balance of power in Spain has now shifted after Los Blancos' 2-1 victory in Catalunya on Saturday.
Certainly, Heynckes is of the opinion that Madrid's triumph has, at the very least, made Bayern's task in Wednesday's second leg at the Santiago Bernabeu even more arduous.
"Until two weeks ago, we said that Barcelona were the benchmark for all things," the Bavarians' boss mused during his pre-game press conference.
"But now Real have won in Barcelona - this makes the game at the Bernabeu a very difficult one for Bayern."
However, Heynckes is hoping that the Blaugrana overcome Chelsea in the other semi-final as he would dearly love to pit his wits against Pep Guardiola.
"I would prefer to face Barcelona if we reach the final.
Turning his attention back to the Catalans' great rivals, Heynckes conceded that Bayern can ill afford to sit back in the hope of keeping a clean sheet against Madrid, in light of their hosts' goalscoring prowess.
"The first leg result is a little advantage for us," he confessed. "But Real have shown this season that they can score a scary amount of goals.
"But we have a good balance between defence and offence, so you can prepare yourselves for a treat of football. This will be a battle of giants."
However, when pressed on how many goals he suspected Bayern might need to go through, Heynckes replied: "I will not speculate about it. It's clear that Real have uncommon attacking potential, but so do Bayern. We are always in a position to score at the Bernabeu."
Bayern's victory at the Allianz Arena last Tuesday was ultimately overshadowed by an altercation between star duo Franck Ribery and Arjen Robben, who reportedly came to blows in the dressing room after an on-field dispute over a free kick.
However, Heynckes insists that the handshake between the pair during the weekend victory over Werder Bremen proves that both men have put the incident firmly behind them.
"This is history," he argued. "Ribery's gesture on Saturday showed that."
Heynckes also claimed that the seven Bayern players who are going into the second leg on yellow cards will not allow the risk of suspension to affect their commitment to the cause.
"I'm not worried, because you can play aggressively without receiving a yellow card," he reasoned.
Marca ran a headline in German ahead of the game at the Bernabeu claiming that 90 minutes represented a long time for Bayern to survive but when this was put to Heynckes, he countered: "I find this very funny, but the 90 minutes can also be very long for Real."
The second-leg showdown in the Spanish capital kicks off at 20.45CET.
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