Andre Villas-Boas reflected on a “gratifying week” and insisted that Chelsea can overhaul Manchester City’s seven-point gap over his team to win the Premier League title this season.Chelsea condemned City to their first league defeat with a 2-1 victory at Stamford Bridge, a result which Villas-Boas believes opens up the race at the summit.“Seven points is nothing in this league, with so many teams competing for the title,” the Chelsea manager said in his post-match press conference.“Man City, Tottenham, Liverpool are strong and solid, Arsenal are coming from the death to recover their title hopes. I cannot recall so many teams competing and feeling strong for the title challenge.“Man City play Arsenal next week, we play Tottenham. So many things are happening. For our title challenge to continue to be alive we must be competent in December and see where we are in January."It depends on what we continue to do but shortening the lead is good for us.”Chelsea recovered from Mario Balotelli’s second-minute goal and an early City onslaught to record a third consecutive win, coming five days after the 3-0 Champions League win over Valencia.Villas-Boas said: “I’m very happy. It’s been a very gratifying week for us. It was a very good win for the players. Going 1-0 down made things very difficult - it gave Man City even more motivation and belief to get a good result.“We showed good strength of character and resilience. We did very well in the second half to find the details we needed to get the three points. We deserve credit for what we are achieving after a bad run of results.”The Portuguese also revealed that Frank Lampard persuaded designated penalty-taker Juan Mata to let him take the decisive second-half spot-kick from which he emphatically scored the winner.“We assigned Didier Drogba and Mata the penalty duties beforehand,” explained Villas-Boas.“As you could see Mata was going to take it but Lamps had a word with Mata, was feeling confident and Mata gave him the chance to take it.”