Federer is aiming to triumph at the Swiss indoors again, having won the competition eight times throughout his glittering career.
The 37-year-old’s mast scalp in Basel came against Juan Martin del Potro, beating the Argentine 6-7, 6-4, 6-3 in last year’s final.
Roger Federer has started this year’s competition sluggishly, though, needing all three sets to beat Filip Krajinovic 6-2, 3-4, 6-4.
And Sky Sports pundit Maclagan has urged him to improve his serve if he is to have any chance of winning the tournament for a stunning ninth time.
He said: “He has made it through by the skin of his teeth.
“There are supporters in here who need a drink and he may wonder how he got through because he cannot of felt confident.
“The serve was not good, the forehand breaking down but somehow he got over the line.
“Roger Federer in terms of numbers, it just wasn’t convincing at all.
“Only 47% of first serves in and he finished better than he started when it was way down in the 30s.”
Meanwhile, Federer himself has admitted he was far from his best against Krajinovic.
“I didn’t serve very well [against first-round opponent Filip Kranjovic,” Federer said.
“I think I was misfiring the corners, I was not hitting the lines enough.
“Clearly you make your life more difficult, but still I was up 6-2, 3-1, break points, so things could have ended very quickly today, even though I didn’t have the best serve percentage stats.
“But maybe that’s exactly what caught up to me eventually. It’s just getting used to it. This is where the first rounds can be tricky.”
Federer is next in action against Jan-Lennard Struff tonight (6pm).
The veteran has won all three of their meetings in the past.
The last was back in July at Wimbledon.