The semi-finals will be played in a home and away format with the winners over the two legs playing the final on April 12 at the home of the higher-ranked team in the league table.
The Mariners looked the better side and had the best chance of the first-half in the 40th minute but Williams' powerful left-footer rattled off the upright.
The five-time Ballon d'Or winner, who has made no secret of his ambition to reach 1,000 career goals, reiterated earlier this month that he has no plans to slow down, even if his family thinks otherwise.
ISL clubs warn AIFF of possibility of their shutting down entirely if current impasse not resolved
The Mariners had successfully defended their ISL Shield to book a direct berth in ACL 2, finishing eight points clear of FC Goa.
FC Goa missed the chance to enter the second leg of their Indian Super League (ISL) semi-finals with an advantage as they squandered a lead twice in their 2-2 draw against Mumbai City FC
Igor Angulo's sixth goal of the season propelled FC Goa to their second win on the trot, as they got the better of Odisha FC 1-0, on Saturday.
Chennaiyin FC added to FC Goa's misery by handing them a 2-0 defeat, the latter's third successive loss in the 3rd season of the Indian Super League at Jawaharlal Nehru Stadium, in Chennai, on Thursday.
AIFF to name head coach on Aug 1; Jamil front-runner but Constantine not ruled out
'Everyone knows what is at stake, and the approach and mindset that we need in these matches.'
Former Chief Justice of Bombay High Court, Kshitij Vyas, will pronounce his verdict next week over FSDL and FC Goa's appeal against sanctions imposed on them by Indian Super League's Regulatory Commission for boycotting the prize distribution ceremony following last edition's Indian Super League final.
The All India Football Federation (AIFF) has issued a show cause notice to FC Goa, asking them to explain why disciplinary action should not be taken against them for the fracas after their defeat to Chennaiyin FC in the final of Indian Super League (ISL) on December 20.
The senior India squad began its preparatory camp in Bengaluru on August 15 ahead of next month's CAFA Nations Cup, but 13 players, including seven from Mohun Bagan, have skipped the camp.
Inter Kashi filed an appeal at the Switzerland-based CAS on April 24 against the decision of the AIFF appeals committee and the world's apex sports tribunal ruled in favour of the club on Tuesday.
FC Goa have made their life difficult for themselves after being held to a goalless draw by Mumbai City FC in a crucial round-robin fixture of the Indian Super League football tournament, in Margao on Wednesday.
SCEB failed to make use of a numerical advantage to settle for a 1-1 draw against FC Goa
The second half saw Persepolis create a number of chances yet again, but were thwarted on each occasion thanks to some excellent rear-guard action from the FC Goa defence.
Indian Super League side FC Goa, which was slapped a Rs 11 crore fine and their co-owners Shrinivas Dempo and Dattaraj Salgaocar banned for two and three seasons respectively, has challenged the order of the tournament's regulatory commission.
FC Goa on became the first team from the country to secure a berth in the group stage of the AFC Champions League, the continent's top-tier club competition, after beating Jamshedpur FC 5-0 in an Indian Super League match, in Jamshedpur, on Wednesday.
Both Churchill Brothers and Inter Kashi celebrated after their respective matches on Sunday.
Now AIFF's move to hand the trophy to Churchill Brother, just hours after the CAS order staying the federation's decision to declare the club as champions, could provoke international scrutiny, including from FIFA.
All the results from the I-League and ISL matches played on Saturday
In its immediate next step, the club is in the process of appointing a Technical Director, who has the relevant coaching experience and scouting knowledge within the Indian footballing ecosystem.
Striker Ferran Corominas scored the first hat-trick of the season as FC Goa beat 10-man Bengaluru FC 4-3 in a thrilling match of the Indian Super League in Margao on Thursday.
FC Goa returned the favour just four minutes later when Seriton Fernandes and Alberto Noguera played a quick one-two, before sending the former free on the right flank.
A brace from Jorge Ortiz helped FC Goa script a 3-0 win over Jamshedpur FC in an Indian Super League match at the Fatorda Stadium, in Margao, on Thursday.
Uruguayan striker Emiliano Alfaro struck twice to help NorthEast United FC beat FC Goa 2-0 and register their second consecutive win in the Indian Super League football in Guwahati on Tuesday.
India defender Subhasish Bose named men's player of the year; Soumya wins in women's section
Indian Super League side FC Goa have been slapped with a fine of Rs 4,40,000 ($6,537) for two separate incidents of team misconduct while two of its players were suspended for two matches each for "offensive behaviour" by All India Football Federation's Disciplinary Committee.
Brisbane Roar to 5-1 win over Dempo FC in their opener at the Bhausaheb Bandodkar Memorial Trophy on Saturday.
Iain Hume's 23rd minute goal proved the decisive winner as Kerala Blasters beat Pune City FC to book a semi-final spot in the Hero Indian Super League.
Inter Kashi to appeal the decision to CAS.
FC Goa struck late to floor NorthEast United FC 2-1 for their first home win this season in the Hero Indian Super League on Friday.
All the results from the I-League and ISL matches played on Friday
Chennaiyin FC outplayed FC Goa 3-0 with a dominant performance in the second leg of the Indian Super League (ISL) semifinal to advance to the final against Bengaluru FC on 4-1 aggregate, in Chennai, on Tuesday.
Los Angeles Dodgers star Mookie Betts bought the first announced team in the WBL, which is yet to announce the franchises and schedule of the first event of the league featuring mixed-gender teams.
FC Goa were off to a flyer as Guarrotxena scored after just two minutes. Brandon Fernandes played a short corner to Edu Bedia on the right flank. The Spaniard whipped a cross in as the ball missed a cheeky flick from Redeem Tlang before finding Guarrotxena, whose decisive tap-in put the Gaurs ahead.
The Indian men's U-23 team suffered a heartbreaking 2-3 defeat against Tajikistan in a thrilling international friendly at the TALCO Arena in Tursunzoda on Wednesday.
Jamil will succeed Spaniard Manolo Marquez, who parted ways with the AIFF last month following India's recent struggles.
FC Goa humiliated Chennaiyin FC in-front of their home crowd with 3-1 win to clinch a semi-final berth in the Indian Super League on Friday.
