Inter wasn't very superior in the match against Lazio but they could play more effective. Lazio played not very badly, they actually could give good challenge to Inter Milan. However, Inter Milan has a better quality of attackers, they sill could score 2 goals although the match was very tight. 4 point difference seems not very safe for Inter Milan, Juventus still has a big chance to overtake it. But winning the match brings positive impacts for Inter players, they will be more confident for the next matches.
Inter Milan can prove that they are still the best in the Italian League no matter who the opponent is, Inter still collects points in every match so this is what Inter needs to do and slowly they will leave Juventus behind, difference of 4 points is not safe enough for Inter Milan but it is the first step to winning the title compare with a few weeks ago when Juventus was at the top of the standings of course 4 points ahead is better. One match that can be decisive is when Juventus plays Inter Milan in February so there we will see who is more worthy to win the title, usually whoever wins an important match has the potential to win the title and we have to wait the next few months.