The 39-time champions will meet Saurashtra in the final to be played in Mumbai from January 26-30.
Mumbai dismissed Services for 240 on the sixth day to take a huge first innings lead of 214 runs, which sealed a spot in the title round.
A champion team knows pretty well as to when they should play their 'A' game and that's exactly what Ajit Agarkar's men did on the final day.
Starting on 164 for three, overnight not out batsmen Soumya Swain (74) and Yashpal Singh (58) took the score to 186 but suddenly the home team lost seven wickets for 54 runs in little over 27 overs.
Seamer Dhawal Kulkarni bowled in right areas to end with figures of five for 33 as he cleaned up the lower order in a jiffy.
Once Yashpal, who looked good during his 96-ball knock, poked at a good length delivery from seamer Shardul Thakur to be caught by Aditya Tare, the institutional team ran out of steam.
Swain, who top-scored with 74 that had eight boundaries literally gave catching practice to Wasim Jaffer at first-slip off left-arm spinner Vishal Dabholkar delivery as Services were reduced to 195 for six.
After that it was a matter of time as Dhawal pitched the ball up and lower-order batsmen neither had the technique nor self-belief to defend.
"It's a relief that it's over finally and we didn't want it to be decided on spin of coin. Obviously the pitch had flattened out due to the sun beating down and it became a bit easier for batting," a satisfied Agarkar told mediapersons at the end of the match.
"I thought that we could have got one more wicket yesterday evening but then we always knew that it was a matter of seven good deliveries," the former India speedster said.
Agarkar informed that he doesn't have an idea whether Zaheer Khan will be fit in time for the final match and looked like he is not expecting Rohit Sharma to be released by the Indian team management.
"He is in the Indian squad. Why should he be released when he has just been named in the squad for the last two matches," the skipper said.
Agarkar feels that even if Cheteshwar Pujara doesn't play, it won't make Saurashtra a lesser opponent.
"They have beaten a side like Punjab without Pujara. That says it all."
Agarkar had been a part of six Ranji Trophy winning squads and asked about last one when his brilliant bowling helped Mumbai edge out Karnataka by six runs during the 2009-10 edition, he smiled and replied, "I hope it doesn't get as close as that match."
Brief Scores: Mumbai: 454/8 decl. Services: 240 all out in 91.4 overs (Soumya Swain 74, Yashpal Singh 58, Dhawal Kulkarni 5/33).