Martin O'Neill, Leicester's manager, was understandably "very disappointed" after watching his side dominate their relegation-threatened opponents only to throw away two priceless points in their own bid to ensure Premiership survival ahead of next Sunday's Worthington Cup final.
However, in truth, if Leicester continue to play as they did in the second half yesterday, they need have few worries on that score.
Charlton, though, were staring a miserable return journey to south London in the face after a curiously inept performance that suggested last week's defeat by 10-man Coventry had taken a huge toll on their confidence. But then up stepped Mendonca, only recently back from a lengthy injury, to take advantage of a defensive mistake by Gerry Taggart and steal a typical poacher's goal.
It was particularly harsh on Taggart as the Ulsterman had played a large part in the goal that had given Leicester the lead on the hour. Winning the ball deep inside his own half and setting off up Leicester's left flank, he swapped passes twice with Neil Lennon, who was hugging the touchline. Eventually the latter was left with little option but to shoot from an unlikely angle and distance but the ball arced perfectly beyond Sasa Ilic and in off the far post.
Alan Curbishley, the Charlton manager, responded with a triple substitution, including the introduction of Mendonca as well as John Barnes. But when, a minute later, Keith Jones was dismissed for a second bookable offence after fouling Emile Heskey as the Leicester striker broke clear, Charlton's hopes seemed to have faded. Jones had earlier been booked for dissent.
But then with the referee, Alan Wilkie, checking his watch, Leicester lost possession and Charlton won a throw-in 30 yards from goal on the right. Danny Mills took it, aiming for length, and the ball flew off Taggart's head straight to the feet of Mendonca in the six-yard area. The striker accepted the chance with glee.
"We played particularly badly - we know that - and to get a point in the manner we got it is fantastic," Curbishley said. "I've said to the players, `You don't know how important that's going to be'." Curbishley's assistant, Mervyn Day, was, according to the visiting manager, "sent off" by Wilkie for persistent verbal abuse, and Charlton now await the referee's report.
By a quirk of the fixture list Charlton now have a three-week break before their next game and, thanks to Mendonca, they begin it one point clear of the relegation zone. Leicester, meanwhile, must pick themselves up again and a day out at Wembley is probably as good a way of doing it as any.