Striker Max Miller gave the hosts the lead in the 41st minute before Ethan Prichard levelled on the hour mark. Hill went in front once more through Lewis Finney only for Mendoza to grab a share of the spoils with a superb equaliser on 90 minutes.
There was only one change to the starting XI that drew 1-1 with East Grinstead last time out at Oaklands Park on Good Friday, when Josh Clack scored in stoppage time, as Lewis Hyde returned to the line-up in place of Kaleem Haitham.
Chichester won the reverse fixture at the start of February snapping a sequence of five straight Isthmian south east wins for the Hillians, then the division’s in-form side, courtesy of first half goals from Callum Overton and Lloyd Rowlatt.
The home team, seventh in the league, began brightly but Jamie Horncastle got in a nice early tackle on Elliot Cross.
Hyde then did well to concede a throw ahead of Miller who was involved moments later getting the ball down skilfully and whipping over a dangerous cross.
Chi keeper Kieran Magee spilled Charlie Kelly’s delivery to Pat Harding, making his 463rd and final home appearance in eleven seasons at Burgess Hill, only for Ben Pashley to hook the ball away.
A neat piece of play by Mendoza won the visitors a throw which came to Pashley who crossed into Will Huffer’s gloves four minutes in.
Next Ryan Davidson held off Tom Chalaye after the Hill No10 and Kelly probed.
Tyrone Madhani’s delivery was then headed clear as Chi countered before the first clear cut chance came and went when the ball bobbled for Prichard after a sharp twist and turn.
Rob Hutchings headed back safely to Magee and at the other end a slip by Magee’s counterpart led to Huffer scrambling the loose ball out for another throw.
Chalaye got past Pashley easily enough but Hyde was there to cover and a slick move involving Miller, Chalaye and Kelly similarly fizzled out.
Referee Jamaal Horne didn’t think Hyde had handled in the box on 14 minutes and then Clack had a go only for a defender to get a boot to his effort.
Hyde shielded the ball effectively to deny Chalaye just before Chi won the first corner which Madhani whipped in deep to Horncastle.
Pashley was burned again, by Kelly on this occasion, who couldn’t get a shot off at the mid-point.
Hyde then cleared a cross and Emmett Dunn made a well-timed challenge.
Lovely skill from Finney earned the hosts a corner that Chalaye took short to Finney who picked out Josh Spinks for a free-header straight at Magee.
Chi then survived a heart-in-your-mouth moment when Mendoza’s touch might have gone past Magee.
Both teams exchanged corners either side of the half hour which came to nothing before Kelly’s downward attempt went wide.
Kelly and Cross skewed other attempts wide, and Horncastle’s hit deflected off an opponent for a corner kick.
Miller, Chalaye and Kelly gave the Chi back-line something to think about before Miller broke the deadlock with a fine header – guiding Spinks’ cross into the bottom corner.
And then Pashley, in what would prove to be his last action of the encounter, broke up the danger posed by Harding and Leon Moore.
Baffins Milton Rovers dual-signee Stan Bridgman, who featured for Chi against Folkestone Invicta in the Velocity Trophy, replaced Pashley at the interval and Horncastle dropped back to partner Hyde in the heart of the Chi defence.
Madhani set up Prichard for the opening opportunity of the second half and the No11 pulled a decent save out of Huffer.
The subsequent corner by Madhani brushed the woodwork before a surging run from Davidson gave the hosts further trouble.
Hyde was well-in on Miller turning the ball out for a throw and Harding fizzed a cross over onto the roof of the net.
Davidson then struck a shot narrowly off target following a slick exchange of passes.
Horncastle was in the right place at the right time to deny Miller before Finney hit one high over the bar on the hour.
And it was all square sixty seconds later when a great first touch by Prichard allowed him to cut inside and unleash a drive which beat Huffer all ends up.
Parity didn’t last long though as Hutchings conceded a free-kick when he might have just hacked the ball away. Kelly found Finney with the set-piece and he glanced a header beyond Magee to make it 2-1.
Clack fired an effort wide as Chi sought to respond and Mendoza let the ball run between his legs to Clack who teed his teammate up for a shot which Huffer saved comfortably.
Hyde received a yellow card for pulling Chalaye down on 69 minutes. Kelly took this once again but Hyde got something on it and Magee claimed.
Madhani and Kelly sent a long-ranger and a header over respectively before Dunn had an effort cleared by a centre back.
Chalaye might then have got in when Horncastle lost the ball but the Chi player recovered and snuffed out the danger.
With 10 minutes to go a Davidson snap-shot drifted wide of the mark before Martyn Box came on for Chalaye.
Harding, scorer of the consolation in Hill’s 2-1 loss at Oaklands, was then denied a fairy tale ending when his effort was blocked and the follow-up blazed over.
Alex Weinberger replaced Madhani in the 82nd minute ahead of a fierce Dunn shot which cracked the left-hand stick and rolled agonisingly along the goal line.
The game, played in the right spirit, got a little scrappy with Burgess Hill looking to protect their advantage but Weinberger and Clack linked up in the last minute of normal time and Mendoza’s cute finish handed Chi a point
Harding left the field to a guard of honour on the final whistle.
So, after two Covid-curtailed seasons, Chi will complete a first ever campaign at Step 4 on Saturday 23rd April (Kick Off 3pm) when they welcome Ramsgate to Oaklands Park.
Chichester – Magee, Davidson, Hutchings, Horncastle, Hyde, Pashley, Mendoza, Dunn, Clack, Madhani, Prichard. Subs: (Coote, Weinberger, Bridgman, Carroll)