Inter were lucky that they were able to equalized so quickly, I think that if Juventus were able to hold onto the winning score longer it might have forced Inter to make more mistakes in wanting to score, but Inter quickly equalized and looked more active in wanting to win. A draw was a more acceptable result for Inter than for Juventus, as they were able to maintain their advantage in the away match.
It was not a luck that Inter Milan could equalize the score quickly, they did good efforts. They even played better in the match, they dominated the ball possessions and they made more shots attempts. I think we can say that Juventus was lucky because Inter didn't score more goals, Inter missed some shot attempts. If Inter players have a better accuracy in shooting, Inter probably wins the match. However, everyone agrees that a draw was a fair result for the match, each team gets 1 point in the match.
Maybe if Juventus didn't use a defensive strategy then it might be true that Inter Milan could score more goals. But Allegri made the right steps by continuing to make his squad strengthen its defense even more. Because Allegri seems to know that his squad is not really ready to beat Inter Milan. So we can understand the reasons behind the formation used by Juventus in this match.
And Juventus actually has the opportunity to overtake Inter Milan next week. Because Juventus have a much easier opponent next week, namely against Monza. Meanwhile, Inter Milan has a very strong opponent, namely Napoli. And Napoli will host the match next week. So Juventus can only hope that Inter Milan will lose to Napoli. And Juventus must be able to beat Monza and get full points.